Disc Brakes Buick LeSabre VIII

Hydraulic Brake Master Cylinder Fluid Reservoir

Contains supply of brake fluid for the hydraulic brake system.

Hydraulic Brake Master Cylinder

Converts mechanical input force into hydraulic output pressure. Hydraulic output pressure is distributed from the master cylinder through 2 hydraulic circuits, supplying diagonally-opposed wheel apply circuits.

Hydraulic Brake Pressure Balance Control System

Regulates brake fluid pressure delivered to hydraulic brake wheel circuits, in order to control the distribution of braking force. Pressure balance control is achieved through Dynamic Rear Proportioning (DRP), which is a function of the ABS modulator. See appropriate ANTI-LOCK article in BRAKES for specific information on the operation of DRP.

Hydraulic Brake Pipes and Flexible Brake Hoses

Carries brake fluid to and from hydraulic brake system components.

Hydraulic Brake Wheel Apply Components

Converts hydraulic input pressure into mechanical output force.

HYDRAULIC BRAKE SYSTEM OPERATION

Mechanical force is converted into hydraulic pressure by the master cylinder, regulated to meet braking system demands by the pressure balance control system, and delivered to the hydraulic brake wheel circuits by the pipes and flexible hoses. The wheel apply components then convert the hydraulic pressure back into mechanical force which presses linings against rotating brake system components.

Brake Pedal

Receives, multiplies and transfers brake system input force from driver.

Brake Pedal Pushrod

Transfers multiplied input force received from brake pedal to brake booster.

Vacuum Brake Booster

Uses source vacuum to decrease effort required by driver when applying brake system input force. When brake system input force is applied, air at atmospheric pressure is admitted to the rear of both vacuum diaphragms, providing a decrease in brake pedal effort required. When input force is removed, vacuum replaces atmospheric pressure within the booster.

Vacuum Source

Supplies force used by vacuum brake booster to decrease brake pedal effort.

Vacuum Source Delivery System

Enables delivery and retention of source vacuum for vacuum brake booster.

BRAKE ASSIST SYSTEM OPERATION

Brake system input force is multiplied by the brake pedal and transferred by the pedal pushrod to the hydraulic brake master cylinder. Effort required to apply the brake system is reduced by the vacuum brake booster.

Brake System

The IPC illuminates the brake indicator when the following occurs

1. The IPC detects that the park brake is engaged (signal circuit is low). If the vehicle travels 10-50 feet (3-15.2 meters) with the park brake engaged, the IPC sends a class 2 message to the radio in order to activate an audible warning.
2. The IPC detects a low brake fluid condition (signal circuit is low). The IPC sends a class 2 message to the radio in order to activate an audible warning.
3. The electronic brake control module (EBCM) detects a failure in the braking system. The IPC receives a class 2 message from the EBCM requesting illumination. The IPC sends a class 2 message to the radio in order to activate an audible warning.
4. The IPC performs the displays test at the start of each ignition cycle. The indicator illuminates for approximately 5 seconds.
5. The IPC detects a loss of class 2 communications with the EBCM and the discrete back-up ABS indicator signal circuit is high.

Brake Fluid Low - 37 (With DIC)

The IPC illuminates the BRAKE FLUID LOW - 37 indicator in the DIC when the IPC detects a low brake fluid condition (signal circuit is low). The IPC sends a class 2 message to the radio in order to activate an audible warning.

Park Brake Set - 147 (With DIC)

The IPC illuminates the PARK BRAKE SET - 147 indicator in the DIC when the IPC detects that the park brake is engaged (signal circuit is low). If the vehicle travels 10-50 feet (3-15.2 meters) with the park brake engaged, the IPC sends a class 2 message to the radio in order to activate an audible warning.

BRAKE WARNING SYSTEM DESCRIPTION - LESABRE

The IPC illuminates the brake indicator when any of the following occur

1. The IPC detects that the park brake is engaged. If the vehicle travels 10-50 ft (3-15.2 m) with the park brake engaged, the IPC sends a class 2 message to the BCM in order to activate an audible warning.
2. The IPC detects a low brake fluid condition. The IPC sends a class 2 message to the BCM in order to activate an audible warning.
3. The IPC performs the displays test at the start of each ignition cycle. The indicator illuminates for approximately 5 seconds.
4. The IPC detects a loss of class 2 communications with the EBCM and the discrete back-up ABS indicator signal circuit is high.

Disc Brake Pads

Applies mechanical output force from the hydraulic brake calipers to friction surfaces of brake rotors.

Disc Brake Rotors

Uses mechanical output force applied to friction surfaces from the disc brake pads to slow speed of tire and wheel assembly rotation.

Disc Brake Pad Hardware

Secures disc brake pads firmly in proper relationship to the hydraulic brake calipers; enables a sliding motion of brake pads when mechanical output force is applied.

Disc Brake Caliper Hardware

Provides mounting for hydraulic brake caliper and secures the caliper firmly in proper relationship to caliper bracket. Enables a sliding motion of the brake caliper to the brake pads when mechanical output force is applied.

DISC BRAKE SYSTEM OPERATION

Mechanical output force is applied from the hydraulic brake caliper pistons to the inner brake pads. As the pistons press the inner brake pads outward, the caliper housings draw the outer brake pads inward. This allows the output force to be equally distributed. The brake pads apply the output force to the friction surfaces on both sides of the brake rotors, which slows the rotation of the tire and wheel assemblies. The correct function of both the brake pad and brake caliper hardware is essential for even distribution of braking force.

PARK BRAKE SYSTEM DESCRIPTION

Note. Plastic coated park brake cables do not need periodic lubrication.

Coated park brake cables are used to reduce apply effort and increase corrosion protection. The cables are coated with a plastic material which slides against nylon seals inside the conduit end fittings.

The park brake lever has an indicator switch which closes when the park brake is set, thus illuminating the Red BRAKE lamp.

Park brake lever/cable adjustment is automatic. Cycling the lever 2 to 3 times should result in properly adjusting the park brake after disabling it for service.

Park brake application is completely independent of the hydraulic brake system. The park brake system is a mechanical system which operates the rear disc brakes through the calipers. The system is activated by depressing the park brake pedal, which applies the rear disc brakes via cables. When the park brake is set and the ignition switch is on, the BRAKE warning lamp on the instrument panel will be on. The park brake is released by pushing the pedal down until a click is heard and then releasing. The pedal will click again and the BRAKE lamp in the instrument panel will go out when the park brake system is fully released.

Filling Reservoir

When adding fluid to the brake master cylinder reservoir, use only Delco Supreme 11(R), GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container. The use of any type of fluid other than the recommended type of brake fluid, may cause contamination which could result in damage to the internal rubber seals and/or rubber linings of hydraulic brake system components.

Avoid spilling brake fluid onto painted surfaces, electrical connections, wiring, or cables. Brake fluid will damage painted surfaces and cause corrosion to electrical components. If any brake fluid comes in contact with painted surfaces, immediately flush the area with water. If any brake fluid comes in contact with electrical connections, wiring, or cables, use a clean shop cloth to wipe away the fluid.

1. Visually inspect the brake fluid level through the brake master cylinder reservoir.
2. If the brake fluid level is at or below the half-full point during routine fluid checks, the brake system should be inspected for wear and possible brake fluid leaks.
3. If the brake fluid level is at or below the half-full point during routine fluid checks, and an inspection of the brake system did not reveal wear or brake fluid leaks, the brake fluid may be topped-off up to the maximum-fill level.
4. If brake system service was just completed, the brake fluid may be topped-off up to the maximum-fill level.
5. If the brake fluid level is above the half-full point, adding brake fluid is not recommended under normal conditions.
6. If brake fluid is to be added to the master cylinder reservoir, clean the outside of the reservoir on and around the reservoir cap prior to removing the cap and diaphragm. Use only Delco Supreme 11(R), GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.

Brake Bleeding Sequence

BRAKE BLEEDING SEQUENCE

PRESSURE BLEEDING

1. Place a clean shop cloth beneath the brake master cylinder to prevent brake fluid spills.
2. With the ignition OFF and the brakes cool, apply the brakes 3-5 times, or until the brake pedal effort increases significantly, in order to deplete the brake booster power reserve.
3. If you have performed a brake master cylinder bench bleeding on this vehicle, or if you disconnected the brake pipes from the master cylinder, you must perform the following steps: Ensure that the brake master cylinder reservoir is full to the maximum-fill level. If necessary, add Delco Supreme 11(R), GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container. If removal of the reservoir cap and diaphragm is necessary, clean the outside of the reservoir on and around the cap prior to removal. With the rear brake pipe installed securely to the master cylinder, loosen and separate the front brake pipe from the front port of the brake master cylinder. Allow a small amount of brake fluid to gravity bleed from the open port of the master cylinder. Reconnect the brake pipe to the master cylinder port and tighten securely. Have an assistant slowly depress the brake pedal fully and maintain steady pressure on the pedal. Loosen the same brake pipe to purge air from the open port of the master cylinder. Tighten the brake pipe, then have the assistant slowly release the brake pedal. Wait 15 seconds, then repeat steps C - G until all air is purged from the same port of the master cylinder. With the front brake pipe installed securely to the master cylinder, after all air has been purged from the front port of the master cylinder, loosen and separate the rear brake pipe from the master cylinder, then repeat steps C - H . After completing the final master cylinder port bleeding procedure, ensure that both of the brake pipe-to-master cylinder fittings are properly tightened.
4. Fill the brake master cylinder reservoir to the maximum-fill level with Delco Supreme 11(R), GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container. Clean the outside of the reservoir on and around the reservoir cap prior to removing the cap and diaphragm.
5. Install the Master Cylinder Bleeder Adapter (J-35589-A) to the brake master cylinder reservoir.
6. Check the brake fluid level in the Diaphragm Type Brake Pressure Bleeder, or equivalent (J-29532) , or equivalent. Add Delco Supreme 11(R), GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container as necessary to bring the level to approximately the half-full point.
7. Connect the Diaphragm type brake pressure bleeder or equivalent, to the master cylinder bleeder adapter.
8. Charge the pressure bleeder, or equivalent, air tank to 175-205 kPa (25-30 psi).
9. Open the pressure bleeder, or equivalent, fluid tank valve to allow pressurized brake fluid to enter the brake system.
10. Wait approximately 30 seconds, then inspect the entire hydraulic brake system in order to ensure that there are no existing external brake fluid leaks. Any brake fluid leaks identified require repair prior to completing this procedure.
11. Install a proper box-end wrench onto the RIGHT REAR wheel hydraulic circuit bleeder valve.
12. Install a transparent hose over the end of the bleeder valve.
13. Submerge the open end of the transparent hose into a transparent container partially filled with Delco Supreme 11(R), GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.
14. Loosen the bleeder valve to purge air from the wheel hydraulic circuit. Allow fluid to flow until air bubbles stop flowing from the bleeder, then tighten the bleeder valve.
15. With the right rear wheel hydraulic circuit bleeder valve tightened securely, after all air has been purged from the right rear hydraulic circuit, install a proper box-end wrench onto the LEFT FRONT wheel hydraulic circuit bleeder valve.
16. Install a transparent hose over the end of the bleeder valve, then repeat steps 13 and 14 .
17. With the left front wheel hydraulic circuit bleeder valve tightened securely, after all air has been purged from the left front hydraulic circuit, install a proper box-end wrench onto the LEFT REAR wheel hydraulic circuit bleeder valve.
18. Install a transparent hose over the end of the bleeder valve, then repeat steps 13 and 14 .
19. With the left rear wheel hydraulic circuit bleeder valve tightened securely, after all air has been purged from the left rear hydraulic circuit, install a proper box-end wrench onto the RIGHT FRONT wheel hydraulic circuit bleeder valve.
20. Install a transparent hose over the end of the bleeder valve, then repeat steps 13 and 14 .
21. After completing the final wheel hydraulic circuit bleeding procedure, ensure that each of the 4 wheel hydraulic circuit bleeder valves are properly tightened.
22. Close the pressure bleeder, or equivalent, fluid tank valve, then disconnect the pressure bleeder, or equivalent, from the bleeder adapter.
23. Remove the bleeder adapter from the brake master cylinder reservoir.
24. Fill the brake master cylinder reservoir to the maximum-fill level with Delco Supreme 11(R), GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.
25. Slowly depress and release the brake pedal. Observe the feel of the brake pedal.
26. If the brake pedal feels spongy perform the following steps: Inspect the brake system for external leaks. See «BRAKE SYSTEM EXTERNAL LEAK TEST»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under SYSTEM TESTING. Using a scan tool, perform the anti-lock brake system automated bleeding procedure to remove any air that may have been trapped in the BPMV. See appropriate ANTI-LOCK article in BRAKES.
27. Turn the ignition key ON, with the engine OFF. Check to see if the brake system warning lamp remains illuminated.
28. If the brake system warning lamp remains illuminated, See «HYDRAULIC BRAKE SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__hydraulic-brake-system-testing) under SYSTEM TESTING

MANUAL BLEEDING

1. Place a clean shop cloth beneath the brake master cylinder to prevent brake fluid spills.
2. With the ignition OFF and the brakes cool, apply the brakes 3-5 times, or until the brake pedal effort increases significantly, in order to deplete the brake booster power reserve.
3. If you have performed a brake master cylinder bench bleeding on this vehicle, or if you disconnected the brake pipes from the master cylinder, you must perform the following steps: Ensure that the brake master cylinder reservoir is full to the maximum-fill level. If necessary, add Delco Supreme 11(R), GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container. If removal of the reservoir cap and diaphragm is necessary, clean the outside of the reservoir on and around the cap prior to removal. With the rear brake pipe installed securely to the master cylinder, loosen and separate the front brake pipe from the front port of the brake master cylinder. Allow a small amount of brake fluid to gravity bleed from the open port of the master cylinder. Reconnect the brake pipe to the master cylinder port and tighten securely. Have an assistant slowly depress the brake pedal fully and maintain steady pressure on the pedal. Loosen the same brake pipe to purge air from the open port of the master cylinder. Tighten the brake pipe, then have the assistant slowly release the brake pedal. Wait 15 seconds, then repeat steps C - G until all air is purged from the same port of the master cylinder. With the front brake pipe installed securely to the master cylinder, after all air has been purged from the front port of the master cylinder, loosen and separate the rear brake pipe from the master cylinder, then repeat steps C - H . After completing the final master cylinder port bleeding procedure, ensure that both of the brake pipe-to-master cylinder fittings are properly tightened.
4. Fill the brake master cylinder reservoir with Delco Supreme 11(R), GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container. Ensure that the brake master cylinder reservoir remains at least half-full during this bleeding procedure. Add fluid as needed to maintain the proper level. Clean the outside of the reservoir on and around the reservoir cap prior to removing the cap and diaphragm.
5. Install a proper box-end wrench onto the RIGHT REAR wheel hydraulic circuit bleeder valve.
6. Install a transparent hose over the end of the bleeder valve.
7. Submerge the open end of the transparent hose into a transparent container partially filled with Delco Supreme 11(R), GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.
8. Have an assistant slowly depress the brake pedal fully and maintain steady pressure on the pedal.
9. Loosen the bleeder valve to purge air from the wheel hydraulic circuit.
10. Tighten the bleeder valve, then have the assistant slowly release the brake pedal.
11. Wait 15 seconds, then repeat steps 8 - 10 until all air is purged from the same wheel hydraulic circuit.
12. With the right rear wheel hydraulic circuit bleeder valve tightened securely, after all air has been purged from the right rear hydraulic circuit, install a proper box-end wrench onto the LEFT FRONT wheel hydraulic circuit bleeder valve.
13. Install a transparent hose over the end of the bleeder valve, then repeat steps 7 - 11 .
14. With the left front wheel hydraulic circuit bleeder valve tightened securely, after all air has been purged from the left front hydraulic circuit, install a proper box-end wrench onto the LEFT REAR wheel hydraulic circuit bleeder valve.
15. Install a transparent hose over the end of the bleeder valve, then repeat steps 7 - 11 .
16. With the left rear wheel hydraulic circuit bleeder valve tightened securely, after all air has been purged from the left rear hydraulic circuit, install a proper box-end wrench onto the RIGHT FRONT wheel hydraulic circuit bleeder valve.
17. Install a transparent hose over the end of the bleeder valve, then repeat steps 7 - 11 .
18. After completing the final wheel hydraulic circuit bleeding procedure, ensure that each of the 4 wheel hydraulic circuit bleeder valves are properly tightened.
19. Fill the brake master cylinder reservoir to the maximum-fill level with Delco Supreme 11(R), GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.
20. Slowly depress and release the brake pedal. Observe the feel of the brake pedal.
21. If the brake pedal feels spongy, repeat the bleeding procedure again. If the brake pedal still feels spongy after repeating the bleeding procedure, perform the following steps: Inspect the brake system for external leaks. See «BRAKE SYSTEM EXTERNAL LEAK TEST»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under SYSTEM TESTING. Pressure bleed the hydraulic brake system in order to purge any air that may still be trapped in the system.
22. Turn the ignition key ON, with the engine OFF. Check to see if the brake system warning lamp remains illuminated.
23. If the brake system warning lamp remains illuminated, see «BRAKE WARNING INDICATOR ALWAYS ON»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-warning-indicator-always-on) under SYMPTOM TESTING.

MASTER CYLINDER BENCH BLEEDING

When adding fluid to the brake master cylinder reservoir, use only Delco Supreme 11(R), GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container. The use of any type of fluid other than the recommended type of brake fluid, may cause contamination which could result in damage to the internal rubber seals and/or rubber linings of hydraulic brake system components.

1. Secure the mounting flange of the brake master cylinder in a bench vise so that the rear of the primary piston is accessible.
2. Remove the master cylinder reservoir cap and diaphragm.
3. Install suitable fittings to the master cylinder ports that match the type of flare seat required and also provide for hose attachment.
4. Install transparent hoses to the fittings installed to the master cylinder ports, then route the hoses into the master cylinder reservoir.
5. Fill the master cylinder reservoir to at least the half-way point with Delco Supreme 11(R), GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.
6. Ensure that the ends of the transparent hoses running into the master cylinder reservoir are fully submerged in the brake fluid.
7. Using a smooth, round-ended tool, depress and release the primary piston as far as it will travel, a depth of about 1" (25 mm), several times. Observe the flow of fluid coming from the ports. As air is bled from the primary and secondary pistons, the effort required to depress the primary piston will increase and the amount of travel will decrease.
8. Continue to depress and release the primary piston until fluid flows freely from the ports with no evidence of air bubbles.
9. Remove the transparent hoses from the master cylinder reservoir.
10. Install the master cylinder reservoir cap and diaphragm.
11. Remove the fittings with the transparent hoses from the master cylinder ports. Wrap the master cylinder with a clean shop cloth to prevent brake fluid spills.
12. Remove the master cylinder from the vise.

HYDRAULIC BRAKE SYSTEM FLUSHING

1. Inspect the brake fluid for the following conditions, indicating brake fluid contamination: Fluid separation, indicating 2 types of fluid are present; a substance other than the recommended brake fluid has been introduced into the brake hydraulic system Swirled appearance - oil-based substance. Layered appearance - silicone-based substance. Fluid discoloration, indicating the presence of moisture or particles that have been introduced into the brake hydraulic system. Cloudy appearance - moisture. Dark appearance/suspended particles in fluid - dirt, rust, corrosion, brake dust.
2. Inspect the master cylinder reservoir cap diaphragm and the reservoir-to-master cylinder grommets for swelling, indicating brake fluid contamination.
3. If the brake fluid WAS contaminated with an oil-based or a silicone-based substance, indicated by fluid separation and/or a swollen master cylinder reservoir cap diaphragm and/or swollen reservoir-to-master cylinder grommets, perform the following: Remove ALL of the following components listed from the vehicle. Each component contains internal rubber seals/linings which have been contaminated by the contaminated brake fluid in the brake hydraulic system. Refer to the procedures indicated: Master Cylinder Replacement «BRAKE HOSE - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION «BRAKE HOSE - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION «BRAKE CALIPER - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-front) under REMOVAL & INSTALLATION Brake Pressure Modulator Valve (BPMV) Replacement in appropriate ANTI-LOCK article in BRAKES Clean out all the hydraulic brake pipes using denatured alcohol, or equivalent. Dry the brake pipes using non-lubricated, filtered air. Repair or replace ALL of the following components listed and install them to the vehicle. Each component contains internal rubber seals/linings which have been contaminated by the contaminated brake fluid in the brake hydraulic system. Refer to the procedures indicated: Master Cylinder Overhaul or Master Cylinder Replacement ; also perform the following: Clean the brake master cylinder reservoir using denatured alcohol, or equivalent, then dry the reservoir using non-lubricated, filtered air. Inspect the reservoir for cracks and/or damage and replace if necessary. Replace the brake master cylinder reservoir cap diaphragm. «BRAKE HOSE - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. «BRAKE HOSE - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. «BRAKE CALIPER - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under OVERHAUL or «BRAKE CALIPER - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-front) under REMOVAL & INSTALLATION. «BRAKE CALIPER - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-rear) under REMOVAL & INSTALLATION. Brake Pressure Modulator Valve (BPMV) Replacement in appropriate ANTI-LOCK article in BRAKES.
4. If the brake fluid was NOT contaminated with an oil-based or a silicone-based substance, but WAS contaminated with water or dirt, rust, corrosion, and/or brake dust, replace the brake master cylinder reservoir cap diaphragm. The diaphragm may have allowed the moisture or particles to enter the hydraulic system.
5. Fill the brake master cylinder reservoir to the maximum-fill level with Delco Supreme 11(R), GM U.S. P/N 12377967 (GM Canada P/N 992667) or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.
6. Pressure bleed the hydraulic brake system. Begin the procedure with the pressure bleeder reservoir filled to the maximum-fill level with the correct brake fluid as indicated. See «HYDRAULIC BRAKE SYSTEM BLEEDING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) .

Preliminary Inspections

1. Visually inspect easily accessible brake system components for obvious damage and/or leaks which may indicate that the vehicle should not be driven until further inspections have been completed.
2. Inspect the brake master cylinder reservoir fluid level and adjust only if necessary for brake system road testing. See «MASTER CYLINDER RESERVOIR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under BLEEDING, FILLING & FLUSHING BRAKE SYSTEM.
3. Inspect the tire inflation pressures and adjust as necessary.
4. Inspect the tire tread patterns to ensure that they are the same or very similar, especially per axle.
5. Ensure that the vehicle is not loaded unevenly prior to brake system road testing.

Road Testing Procedure

1. Start the engine and allow it to idle.
2. Check to see if the brake system warning lamp remains illuminated.
3. If the brake system warning lamp remains illuminated, DO NOT proceed to test drive the vehicle until it is diagnosed and repaired. See «HYDRAULIC BRAKE SYSTEM DIAGNOSIS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__hydraulic-brake-system-testing) under TROUBLE SHOOTING.
4. Select a smooth, dry, clean and level road or large lot that is as free of traffic and obstacles as possible for brake system low speed road testing.
5. With the transmission in PARK, lightly apply the brake pedal. Observe both the pedal feel and the pedal travel.
6. If the brake pedal apply felt spongy, or the pedal travel was excessive, DO NOT drive the vehicle until it is repaired.
7. If the brake pedal apply did not feel spongy and the pedal travel was not excessive, proceed to next step.
8. Release and apply the brakes.
9. While continuing to apply the brakes, shift the transmission into DRIVE, release the brakes and allow the engine to idle the vehicle away from the stopped position. Observe for a slow release of the brake system.
10. With the aid of an assistant to observe the vehicle's performance from outside of the vehicle, drive the vehicle at a low speed and lightly apply the brakes while driving past the assistant. Have the assistant observe for brake system noise from the side of the vehicle closest to them, while you observe both the pedal effort and the pedal travel.
11. If the brake pedal apply effort was excessive, or the pedal travel was excessive, DO NOT continue to test drive the vehicle until it is repaired.
12. If the brake pedal apply effort was not excessive and the pedal travel was not excessive, proceed to next step.
13. Drive the vehicle in the opposite direction, at the same low speed and lightly apply the brakes while driving past the assistant. Have the assistant observe for brake system noise from the side of the vehicle closest to him.
14. Drive the vehicle at a low speed and shift the transmission into NEUTRAL without applying the brakes. Observe for a rapid deceleration in vehicle speed, indicating possible brake drag.
15. Select a smooth, dry, clean and level road that is as free of heavy traffic as possible for brake system moderate speed road testing.
16. Drive the vehicle at a moderate speed. Observe for a pull and/or incorrect tracking of the vehicle without the brakes applied.
17. While continuing to drive the vehicle at a moderate speed, perform several light applies of the brakes. Observe the pedal effort and the pedal travel, observe for brake system noise, pulsation and/or brake drag.
18. If the brake pedal apply effort was excessive, or the pedal travel was excessive, DO NOT continue to test drive the vehicle until it is repaired.
19. If the brake pedal apply effort was not excessive and the pedal travel was not excessive, proceed to next step.
20. While continuing to drive the vehicle at a moderate speed, perform several moderate applies of the brakes. Observe the pedal effort and the pedal travel, observe for brake system pulsation and/or uneven braking action, either side to side, or front to rear. A small amount of vehicle front end dip is expected during a moderate apply of the brakes.
21. If the brake pedal apply effort was excessive, or the pedal travel was excessive, DO NOT continue to test drive the vehicle until it is repaired.

Adjustment

The stoplight switches are self adjusting when they are installed properly in the fully locked position. The twist lock type switches do not need any further adjustment.

Measurement & Inspection

1. With the ignition OFF and the brakes cool, apply the brakes 3-5 times, or until the brake pedal effort increases significantly, in order to deplete the brake booster power reserve.
2. Install the Brake Pedal Effort Gage (J-28662) to the brake pedal.
3. Measure and record the distance from the brake pedal to the rim of the steering wheel; note the points of measurement.
4. Apply and maintain the brakes with 100 lbs. (445 N) of force to the brake pedal, as indicated on the effort gage.
5. While maintaining 100 lbs. (445 N) of force to the brake pedal, measure and record the distance from the same point on the brake pedal to the same point on the rim of the steering wheel.
6. Release the brakes and repeat steps 4 and 5 to obtain a second measurement. After obtaining a second measurement, proceed to the next step.
7. Average the first and second measurements recorded during the 2 applies of the brakes.
8. Subtract the initial measurement, unapplied, from the averaged, applied measurement to obtain the brake pedal travel distance. Maximum brake pedal travel-measured with the ignition OFF, brake booster power assist depleted, and the brakes cool is 2.24" (57 mm).

Inspection

1. Disconnect the brake pedal pushrod from the brake pedal.
2. Inspect the brake pedal pushrod eyelet bushing for cracks and/or excessive wear.
3. Reposition the pedal pushrod boot toward the front of the vehicle to expose as much of the pedal pushrod as possible.
4. Inspect the brake pedal pushrod for straightness.
5. If the brake pedal pushrod eyelet bushing exhibited cracks and/or excessive wear, then the bushing requires replacement.
6. If the brake pedal pushrod is not straight, then the pushrod requires replacement.
7. Return the pedal pushrod boot to its original position on the pedal pushrod.
8. Connect the brake pedal pushrod to the brake pedal.

1. Visually inspect all of the brake pipes for the following conditions: Kinks, improper routing, missing or damaged retainers Leaking fittings, excessive corrosion
2. If any of the brake pipes exhibited any of the conditions listed, then the identified pipe, or pipes, require replacement.
3. Ensure that the vehicle axles are properly supported at ride height in order to maintain the proper relationship of the flexible brake hoses to the chassis.
4. Visually inspect all of the flexible brake hoses for the following conditions: Kinks, improper routing, twists, chafing, missing or damaged retainers Leaking connections, cracking, dry-rot, blisters, bulges
5. If any of the flexible brake hoses exhibited any of the conditions listed, then the identified flexible brake hose, or hoses require replacement.
6. Squeeze the flexible brake hoses with firm finger pressure to check for soft spots, indicating an internal restriction. Check the entire length of each flexible brake hose.
7. If any of the flexible brake hoses were found to have soft spots, then the identified flexible brake hose, or hoses require replacement.

HYDRAULIC BRAKE COMPONENT OPERATION VISUAL INSPECTION

1. With the tire and wheel assemblies removed and the brake rotors retained by wheel lug nuts, visually inspect the caliper piston dust boot sealing area to ensure that there are no brake fluid leaks.
2. If any evidence of a brake fluid leak is present, the brake caliper requires overhaul or replacement.
3. While the brake system is at rest, observe the position of the caliper piston in relation to the caliper housing.
4. Have an assistant apply and release the brake pedal several times while you observe the operation of the hydraulic brake caliper. Observe the caliper piston for unrestricted and even movement during each apply of the brake system. Observe the caliper piston for an unrestricted and even return motion during each release of the brake system.
5. If the caliper piston did not exhibit unrestricted and even movement during brake system apply and/or release, the piston square seal may be worn or damaged and the caliper may require overhaul or replacement.

BRAKE ROTOR REFINISHING

1. The disc brake rotors do not require refinishing as part of routine brake system service. Do not refinish disc brake rotors in an attempt to correct the following conditions: Brake system noise, squeal, growl, groan. Uneven and/or premature disc brake pad wear. Superficial or cosmetic corrosion/rust of the disc brake rotor surface. Scoring of the disc brake rotor surface less than the maximum allowable specification.
2. Disc brake rotors should only be refinished if the following conditions exist: Excessive corrosion/rust and/or pitting. Cracks and/or heat spots. Excessive blueing discoloration. Scoring of the disc brake rotor surface in excess of the maximum allowable specification. Lateral runout in excess of the maximum allowable specification. Thickness variation in excess of the maximum allowable specification.
3. Inspect each of the disc brake rotors and determine if the rotors can be refinished and remain above the minimum allowable thickness after refinish specification: Inspect the thickness of each of the disc brake rotors. See «BRAKE ROTOR THICKNESS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-rotor-thickness) under ADJUSTMENTS & INSPECTION. Inspect each of the disc brake rotors for excessive surface wear and/or lateral runout. See «BRAKE ROTOR SURFACE & WEAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-rotor-surface-wear) under ADJUSTMENTS & INSPECTION.
4. If the rotors can be refinished, proceed with the rotor refinishing procedure.
5. Use the Rotor Resurfacing Kit (J-41013) in order to thoroughly clean any corrosion from the wheel bearing flange. Use the Wheel Hub Resurfacing Kit (J-42450-A) in order to thoroughly clean any corrosion/rust from the brake rotor mating surface and mounting face. Failure to clean the corrosion from the wheel bearing flange, brake rotor mating surface, and brake rotor mounting face may result in increased lateral runout of the brake rotor and brake system pulsation.
6. Mount the brake rotor to the brake lathe according to the lathe manufacturer's instructions, ensuring that all mounting attachments and adapters are clean and free of debris.
7. Ensure that any vibration dampening attachments are securely in place.
8. With the brake lathe running, slowly bring in the cutting tools until they just contact the brake rotor friction surfaces.
9. Observe the witness mark on the brake rotor. If the witness mark extends approximately three-quarters or more of the way around the brake rotor surface on each side, the brake rotor is properly mounted to the lathe.
10. If the witness mark does not extend three-quarters or more of the way around the brake rotor, re-mount the rotor to the lathe.
11. Following the brake lathe manufacturer's instructions, refinish the brake rotor.
12. After each successive cut, inspect the brake rotor thickness. See «BRAKE ROTOR THICKNESS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-rotor-thickness) under ADJUSTMENTS & INSPECTION.
13. If at any time the brake rotor exceeds the minimum allowable thickness after refinish specification, the brake rotor must be replaced.
14. After refinishing the brake rotor, use the following procedure in order to obtain the desired non-directional finish: Follow the brake lathe manufacturer's recommended speed setting for applying a non-directional finish. Using moderate pressure, apply the non-directional finish: If the lathe is equipped with a non-directional finishing tool, apply the finish with 120 grit aluminum oxide sandpaper. If the lathe is not equipped with a non-directional finishing tool, apply the finish with a sanding block and 150 grit aluminum oxide sandpaper. After applying a non-directional finish, clean each friction surface of the brake rotor with denatured alcohol or an equivalent brake cleaner.
15. Remove the brake rotor from the brake lathe.

PARKING BRAKE

Note. Parking brake is self adjusting. No adjustments are necessary.

TORQUE CONVERTER CLUTCH/CRUISE CONTROL RELEASE SWITCH

Note. Do not depress the brake pedal during the adjustment procedure.

1. Remove the left closeout/insulator panel.
2. Rotate the switch counter-clockwise in order to release the switch from the retainer.
3. Insert the switch into the retainer until the switch is fully seated against the brake pedal arm.
4. Rotate the switch clockwise in order to lock the switch into position. Measure the distance from the end of the barrel on the switch to the pedal arm, ensure that the clearance is 1/16" (1.5-1.7 mm). If the distance is not correct, perform steps 2 and 3 again. The following pedal travel statement may be used in order to inspect for proper adjustment of the release switch: The release switch assembly must be closed at 1/8-1/2" (3.5-12.5 mm) brake pedal travel, measured at the centerline of the brake pedal assembly. Nominal actuation of the release assembly contacts is about 3/16" (4.5 mm).
5. Install the left closeout/insulator panel.

Begin the disc brake system diagnosis with Diagnostic Starting Point - Hydraulic Brakes. See DIAGNOSTIC STARTING POINT - HYDRAULIC BRAKES . The use of the Diagnostic Starting Point will lead to the identification of the correct procedure for diagnosing the system and where the procedure is located.

DIAGNOSTIC STARTING POINT - HYDRAULIC BRAKES

Begin the hydraulic brake system diagnosis with the DIAGNOSTIC SYSTEM CHECK - HYDRAULIC BRAKES . The Diagnostic System Check will provide the following information

1. The identification of the control module(s) which command the system.
2. The ability of the control module(s) to communicate through the serial data circuit.
3. The identification of any stored diagnostic trouble codes (DTCs) and their status.

The use of the Diagnostic System Check will identify the correct procedure for diagnosing the system and where the procedure is located.

DIAGNOSTIC STARTING POINT - PARK BRAKE

Begin the system diagnosis by reviewing the system description and operation. See DESCRIPTION & OPERATION . Reviewing the description and operation information will help you determine the correct symptom diagnostic procedure when a malfunction exists. Reviewing the description and operation information will also help you determine if the condition described by the customer is normal operation. See SYMPTOMS - PARK BRAKE in order to identify the correct procedure for diagnosing the system and where the procedure is located.

DIAGNOSTIC SYSTEM CHECK - HYDRAULIC BRAKES

1. Install a scan tool. Does the scan tool power up? If so, go to next step. If not, go to SCAN TOOL DOES NOT POWER UP in appropriate DATA LINK COMMUNICATION article.
2. Turn ON the ignition, with the engine OFF. Attempt to establish communication with the following control modules: Electronic Brake Control Module (EBCM) Instrument Panel Cluster (IPC) Does the scan tool communicate with all control modules? If so, go to next step. If not, go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE in appropriate DATA LINK COMMUNICATION article.
3. Select the display DTCs function on the scan tool for the following control modules: Electronic Brake Control Module (EBCM) Instrument Panel Cluster (IPC) Does the scan tool display any DTCs? If so, go to next step. If not, go to «SYMPTOMS - HYDRAULIC BRAKE»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__symptoms-hydraulic-brake) .
4. Does the scan tool display any DTCs which begin with a "U"? If so, go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE in appropriate DATA LINK COMMUNICATION article. If not, go to next step.
5. Does the scan tool display DTC B1004 or B1007? If so, go to DIAGNOSTIC TROUBLE CODE (DTC) LIST in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If not, go to next step.
6. Does the scan tool display DTC B1513 or B1514? If so, see DIAGNOSTIC TROUBLE CODE (DTC) LIST in appropriate ENGINE ELECTRICAL article. If not, go to DIAGNOSTIC TROUBLE CODE (DTC) LIST in appropriate ANTILOCK BRAKE SYSTEM article.

Brake Caliper Inspection

1. Inspect the brake caliper housing for cracks, excess wear, and/or damage. If any of these conditions are present, the brake caliper requires replacement.
2. Inspect the caliper piston dust boot seal for cracks, tears, cuts, deterioration and/or improper seating in the caliper body. If any of these conditions are present, the brake caliper requires overhaul or replacement.
3. Inspect for brake fluid leakage around the caliper piston dust boot seal and on the disc brake pads. If there is any evidence of brake fluid leakage, the brake caliper requires overhaul or replacement.
4. Inspect for smooth and complete travel of the caliper piston, or pistons, into the caliper bore, or bores: The movement of a caliper piston into a caliper bore should be smooth and even. If a caliper piston is frozen or difficult to bottom, the caliper requires overhaul or replacement. For single piston caliper applications, insert a discarded inner brake pad or block of wood in front of the piston. Using a large C-clamp installed over the body of the caliper and against the brake pad or block of wood, slowly bottom the piston in the bore. For dual piston caliper applications, insert a discarded inner brake pad or block of wood in front of the pistons. Using 2 large C-clamps installed over the body of the caliper and against the brake pad or block of wood, slowly bottom the pistons evenly into the bores.

Brake Pad Inspection

1. Inspect the disc brake pads at regular intervals, or whenever the tire and wheel assemblies are removed from the vehicle.
2. If replacement is necessary, always replace disc brake pads in axle sets.
3. Inspect both edges of the disc brake pad friction surfaces. The highest rate of wear normally occurs at the trailing edge of the disc brake pads.
4. Inspect the thickness of the disc brake pads in order to ensure that they have not worn prematurely. The disc brake pad wear should be approximately even per axle set.
5. Both front and rear disc brake pads have integral, audible wear sensors. When the disc brake pad wear reaches the minimum allowable thickness, the wear sensor contacts the disc brake rotor. The wear indicator will then produce an audible, high-pitched warning noise during wheel rotation.
6. Replace the disc brake pads when the friction surface is worn to within 0.030" (0.76 mm) of the mounting plates.
7. Remove the brake calipers and inspect the friction surfaces of the inner and outer disc brake pads to ensure that they are level. Place the disc brake pad friction surfaces together and measure the gap between the surfaces. If more than 0.005" (0.13 mm) gap exists midway between the length of the disc brake pads, replace the disc brake pads.
8. Verify that any disc brake pad shims that may be required are in place and not damaged or excessively corroded. Replace any missing or damaged shims in order to preserve proper disc brake performance.
9. Replace the disc brake pads if any have separated from the mounting plates.
10. Inspect the disc brake pads friction surfaces for cracks, fractures, or damage which may cause noise or otherwise impair disc brake performance.

Brake Rotor Thickness

1. Clean the brake pad lining contact surface of the brake rotor with denatured alcohol or an equivalent brake cleaner.
2. Using a micrometer calibrated in ten-thousands of an inch, measure and record the lowest thickness of the brake rotor at 4 or more points, equally spaced around the rotor. Ensure that the measurements are only taken within the brake pad lining contact area and that the micrometer is positioned the same distance from the outside edge of the rotor for each measurement.
3. Compare the lowest thickness measurement recorded to the following specifications: Front brake rotor minimum allowable thickness after refinishing. Rear brake rotor minimum allowable thickness after refinishing. Front brake rotor discard thickness. Rear brake rotor discard thickness. See «DISC BRAKE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__disc-brake-specifications) .
4. If the lowest thickness measurement of the brake rotor is above the minimum allowable thickness after refinishing specification; the rotor may be able to be refinished, depending upon surface and wear conditions which may be present.
5. If the lowest thickness measurement of the brake rotor is at or below the minimum allowable thickness after refinishing specification; the rotor may not be refinished.
6. If the lowest thickness measurement of the brake rotor is at or below the discard thickness specification; the rotor requires replacement.

Brake Rotor Surface & Wear

1. With the tire and wheel assemblies removed and the brake rotors retained by wheel lug nuts, clean the braking (friction) surfaces of the brake rotor with denatured alcohol or an equivalent approved brake cleaner.
2. Inspect the braking surfaces of the brake rotor for the following Braking Surface Conditions: Heavy rust and/or pitting Light surface rust can be removed with an abrasive disc; heavy surface rust and/or pitting must be removed by refinishing the rotor. Cracks and/or heat spots. Excessive blueing discoloration.
3. If the braking surfaces of the brake rotor exhibits one or more of the Braking Surface Conditions, the rotor requires refinishing or replacement.
4. Using a micrometer calibrated in ten-thousands of an inch, measure and record the thickness variation of the brake rotor at 4 or more points, around the rotor. Ensure that the measurements are only taken within the brake pad lining contact area and that the micrometer is positioned the same distance from the outside edge of the rotor for each measurement.
5. Compare the thickness variation recorded to the following specification: Brake rotor maximum allowable thickness variation. See «DISC BRAKE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__disc-brake-specifications) .
6. If the brake rotor thickness variation exceeds the specification, the rotor requires refinishing or replacement.
7. Using the micrometer, measure and record any grooves present on the rotor braking surface.
8. Compare the groove (scoring) depth recorded to the following specification: Brake rotor maximum allowable scoring. See «DISC BRAKE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__disc-brake-specifications) .
9. If the brake rotor scoring depth exceeds the specification, or if an excessive amount of scoring is present, the rotor requires refinishing or replacement.
10. Mount a Dial Indicator, (J-8001) or equivalent, and position the indicator button so it contacts the brake rotor at a 90 degree angle, approximately 0.5" (13 mm) from the rotor's outer edge.
11. Measure and record the lateral runout of the brake rotor. Rotate the rotor until the lowest reading is displayed on the indicator dial, then zero the dial. Rotate the rotor until the highest reading is displayed on the dial. Measure and record the amount of sealed wheel bearing play, then subtract the bearing play from the lateral runout recorded to obtain the true amount of lateral runout.
12. Compare the lateral runout of the brake rotor to the following specification: Front brake rotor maximum allowable lateral runout. See «DISC BRAKE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__disc-brake-specifications) . Rear brake rotor maximum allowable lateral runout. See «DISC BRAKE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__disc-brake-specifications) .
13. If the brake rotor lateral runout exceeds the specification, the rotor requires refinishing or replacement.

Disc Brake Mounting & Hardware - Front

1. Install a large C-clamp, over the body of the brake caliper with the C-clamp ends against the rear of the caliper body and against the outer brake pad.
2. Tighten the C-clamp until the caliper piston is compressed into the caliper bore enough to allow the caliper to slide past the brake rotor.
3. Remove the C-clamp from the caliper.
4. Grasp the brake caliper and try to move the brake caliper up or down. The brake caliper should not have excessive looseness.
5. Grasp the brake caliper and try to move the brake caliper in and out. The brake caliper should slide smoothly with minimal force.
6. Inspect the brake caliper retainers.
7. Inspect the disc brake pad mounting hardware for the following: Bent mounting tabs. Excessive corrosion. Looseness at the brake caliper mounting bracket. Looseness at the disc brake pads. Missing mounting hardware.
8. If any of the conditions listed are found, the disc brake pad mounting hardware requires replacement.
9. Ensure the disc brake pads are held firmly in place on the brake caliper mounting bracket, yet slide easily on the mounting hardware without binding.
10. Inspect the brake caliper bolts for the following: Bent Or Damaged Brake Caliper Bolts Bent Or Damaged Brake Caliper Mounting Bracket Binding Corrosion Cracked Or Torn Boots Looseness In The Brake Caliper Mounting Bracket Missing Boots Seizing
11. If any of the conditions listed are found, the brake caliper mounting hardware requires replacement.

Disc Brake Mounting & Hardware - Rear

1. Compress the piston until resistance is felt, but no more than 1 mm of piston travel.
2. Grasp the brake caliper and try to move the brake caliper up or down. The brake caliper should not have excessive looseness.
3. Grasp the brake caliper and try to move the brake caliper in and out. The brake caliper should slide smoothly with minimal force.
4. Inspect the brake caliper retainers.
5. Inspect the disc brake pad mounting hardware for the following: Bent Mounting Tabs Excessive Corrosion Looseness At The Brake Caliper Mounting Bracket Looseness At The Disc Brake Pads Missing Mounting Hardware
6. If any of the conditions listed are found, the disc brake pad mounting hardware requires replacement.
7. Ensure the disc brake pads are held firmly in place on the brake caliper mounting bracket, yet slide easily on the mounting hardware without binding.
8. Inspect the brake caliper bolts for the following: Bent Or Damaged Brake Caliper Bolts Bent Or Damaged Brake Caliper Mounting Bracket Binding Corrosion Cracked Or Torn Boots Looseness In The Brake Caliper Mounting Bracket Missing Boots Seizing
9. If any of the conditions listed are found, the brake caliper mounting hardware requires replacement.

SYMPTOMS - HYDRAULIC BRAKE

The following steps must be completed before using the symptom tables.

1. Perform the Brake System Vehicle Road Test before using the hydraulic brake symptom tables in order to duplicate the customer's concern. See «BRAKE SYSTEM VEHICLE ROAD TEST»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under ADJUSTMENTS & INSPECTION.
2. Review the system operation in order to familiarize yourself with the system functions. Refer to the following: «BRAKE WARNING SYSTEM»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under DESCRIPTION & OPERATION «HYDRAULIC BRAKE SYSTEM»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under DESCRIPTION & OPERATION «BRAKE ASSIST SYSTEM»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under DESCRIPTION & OPERATION «DISC BRAKE SYSTEM»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under DESCRIPTION & OPERATION

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the brake warning system.
2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Intermittent

Intermittent faulty electrical connections or wiring may be the cause of intermittent conditions. Check for loose, bent or corroded terminals and terminal tension. Check for cut, bare or pinched wiring. Simulate the condition that is potentially causing the intermittent connection, either by wiggling the connections or the wiring, test driving or performing other operations while observing scan tool, DVOM or other testing equipment.

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

1. «BRAKE WARNING INDICATOR ALWAYS ON»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-warning-indicator-always-on)
2. «BRAKE WARNING INDICATOR INOPERATIVE»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-warning-indicator-inoperative)
3. «BRAKE PULSATION»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-pulsation)
4. «BRAKE SYSTEM NOISE»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-system-noise)
5. «BRAKING ACTION UNEVEN»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes)
6. «BRAKE PEDAL EXCESSIVE TRAVEL»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-pedal-excessive-travel)
7. «BRAKE PEDAL EXCESSIVE EFFORT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-pedal-excessive-effort)
8. «BRAKES DRAG»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brakes-drag)
9. «BRAKE SYSTEM SLOW RELEASE»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-system-slow-release)
10. «BRAKE FLUID LOSS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-fluid-loss)
11. «PARK BRAKE WILL NOT HOLD OR RELEASE»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__park-brake-will-not-hold-or)

SYMPTOMS - PARK BRAKE

See PARK BRAKE SYSTEM DESCRIPTION under DESCRIPTION & OPERATION.

1. Inspect for aftermarket devices which could affect the operation of the park brake system.
2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

See PARK BRAKE WILL NOT HOLD OR RELEASE under SYMPTOM TESTING.

PARK BRAKE WILL NOT HOLD OR RELEASE

1. Were you sent here from TROUBLESHOOTING? If so, go to next step. If not, go to «DIAGNOSTIC STARTING POINT - HYDRAULIC BRAKES»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__diagnostic-starting-point-hydraulic-brakes) under TROUBLESHOOTING.
2. Inspect the park brake system for proper operation. See «PARK BRAKE SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__park-brake-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to step 5 . If not, go to next step.
3. Inspect the disc brake system for proper operation. See «DISC BRAKE SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__disc-brake-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to step 5 . If not, go to next step.
4. Inspect the hydraulic brake system for proper operation. See «HYDRAULIC BRAKE SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__hydraulic-brake-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to next step.
5. Road test the vehicle in order to confirm proper operation. See «BRAKE SYSTEM VEHICLE ROAD TEST»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under TROUBLE SHOOTING. Is the condition still present? If so, go to step 2 . If not, the system should be okay.

Pulls To One Side

1. Were you sent here from TROUBLESHOOTING? If so, go to next step. If not, go to then go to «DIAGNOSTIC STARTING POINT - HYDRAULIC BRAKES»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__diagnostic-starting-point-hydraulic-brakes) under TROUBLESHOOTING.
2. Inspect the suspension system for proper operation. Did you find and correct a condition? If so, go to step 6 . If not, go to next step.
3. Inspect the steering system for proper operation. Did you find and correct a condition? If so, go to step 6 . If not, go to next step.
4. Inspect the hydraulic brake system for proper operation. See «HYDRAULIC BRAKE SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__hydraulic-brake-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to step 6 . If not, go to next step.
5. Inspect the disc brake system for proper operation. See «DISC BRAKE SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__disc-brake-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to next step.
6. Road test the vehicle in order to confirm proper operation. See «BRAKE SYSTEM VEHICLE ROAD TEST»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under TROUBLE SHOOTING. Is the condition still present? If so, go to step 2 . If not, the system should be okay.

Front To Rear

1. Were you sent here from TROUBLE SHOOTING? If so, go to next step. If not, go to «DIAGNOSTIC STARTING POINT - HYDRAULIC BRAKES»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__diagnostic-starting-point-hydraulic-brakes) under TROUBLE SHOOTING.
2. Inspect the suspension system for proper operation. Did you find and correct a condition? If so, go to step 6 . If not, go to next step.
3. Inspect the hydraulic brake system for proper operation. See «HYDRAULIC BRAKE SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__hydraulic-brake-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to step 6 . If not, go to next step.
4. Inspect the disc brake system for proper operation. See «DISC BRAKE SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__disc-brake-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to step 6 . If not, go to next step.
5. Inspect the brake assist system for proper operation. See «BRAKE ASSIST SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-assist-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to next step.
6. Road test the vehicle in order to confirm proper operation. See «BRAKE SYSTEM VEHICLE ROAD TEST»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under TROUBLE SHOOTING. Is the condition still present? If so, go to step 2 . If not, the system should be okay.

BRAKE FLUID LOSS

1. Were you sent here from TROUBLE SHOOTING? If so, go to next step. If not, go to «DIAGNOSTIC STARTING POINT - HYDRAULIC BRAKES»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__diagnostic-starting-point-hydraulic-brakes) under TROUBLE SHOOTING.
2. Inspect the hydraulic brake system for proper operation. See «HYDRAULIC BRAKE SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__hydraulic-brake-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to step 4 . If not, go to next step.
3. Inspect the disc brake system for proper operation. See «DISC BRAKE SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__disc-brake-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to next step.
4. Road test the vehicle in order to confirm proper operation. See «BRAKE SYSTEM VEHICLE ROAD TEST»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under TROUBLE SHOOTING. Is the condition still present? If so, go to step 2 . If not, the system should be okay.

BRAKE PEDAL EXCESSIVE EFFORT

1. Were you sent here from TROUBLE SHOOTING? If so, go to next step. If not, go to «DIAGNOSTIC STARTING POINT - HYDRAULIC BRAKES»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__diagnostic-starting-point-hydraulic-brakes) under TROUBLE SHOOTING.
2. Inspect the brake assist system for proper operation. See «BRAKE ASSIST SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-assist-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to step 5 . If not, go to next step.
3. Inspect the hydraulic brake system for proper operation. See «HYDRAULIC BRAKE SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__hydraulic-brake-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to step 5 . If not, go to next step.
4. Inspect the disc brake system for proper operation. See «DISC BRAKE SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__disc-brake-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to next step.
5. Road test the vehicle to confirm proper operation. See «BRAKE SYSTEM VEHICLE ROAD TEST»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under TROUBLE SHOOTING. Is the condition still present? If so, go to step 2 . If not, the system should be okay.

BRAKE PEDAL EXCESSIVE TRAVEL

1. Were you sent here from TROUBLE SHOOTING? If so, go to next step. If not, go to «DIAGNOSTIC STARTING POINT - HYDRAULIC BRAKES»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__diagnostic-starting-point-hydraulic-brakes) under TROUBLE SHOOTING.
2. Inspect for proper brake pedal travel. See «BRAKE PEDAL TRAVEL»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under ADJUSTMENTS & INSPECTION. Is the brake pedal travel distance within the acceptable limits? If so, go to step 5 . If not, go to next step.
3. Inspect for worn, missing, misaligned, bent or damaged brake pedal system components. For the brake pedal pushrod component inspection, see «BRAKE PEDAL PUSHROD»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under ADJUSTMENTS & INSPECTION. Inspect the brake pedal bushings for excessive wear and/or damage and inspect the brake pedal for a misaligned, bent, and/or damaged condition. Replace the brake pedal system components that are worn, missing, misaligned, bent or damaged. Refer to the following procedures as necessary. «BRAKE PEDAL ASSEMBLY»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. «VACUUM BRAKE BOOSTER»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. Did you find and replace any worn, missing, misaligned, bent or damaged brake pedal system components? If so, go to next step. If not, go to step 5 .
4. Inspect for proper brake pedal travel. See «BRAKE PEDAL TRAVEL»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under ADJUSTMENTS & INSPECTION. Is the brake pedal travel distance within the acceptable limits? If so, go to step 8 . If not, go to next step.
5. Inspect the hydraulic brake system for proper operation. See «HYDRAULIC BRAKE SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__hydraulic-brake-system-testing) . Did you find and correct a condition? If so, go to step 8 . If not, go to next step.
6. Inspect the disc brake system for proper operation. See «DISC BRAKE SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__disc-brake-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to step 8 . If not, go to next step.
7. Inspect the brake assist system for proper operation. See «BRAKE ASSIST SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-assist-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to next step.
8. Road test the vehicle to confirm proper operation. See «BRAKE SYSTEM VEHICLE ROAD TEST»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under TROUBLE SHOOTING. Is the condition still present? If so, go to step 2 . If not, the system should be okay.

BRAKES DRAG

1. Were you sent here from TROUBLESHOOTING? If so, go to next step. If not, go to «DIAGNOSTIC STARTING POINT - HYDRAULIC BRAKES»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__diagnostic-starting-point-hydraulic-brakes) under TROUBLESHOOTING.
2. Inspect the park brake system for proper operation. See «PARK BRAKE SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__park-brake-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to step 5 . If not, go to next step.
3. Inspect the disc brake system for proper operation. See «DISC BRAKE SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__disc-brake-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to step 5 . If not, go to next step.
4. Inspect the hydraulic brake system for proper operation. See «HYDRAULIC BRAKE SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__hydraulic-brake-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to next step.
5. Road test the vehicle to confirm proper operation. See «BRAKE SYSTEM VEHICLE ROAD TEST»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under TROUBLE SHOOTING. Is the condition still present? If so, go to step 2 . If not, the system should be okay.

BRAKE SYSTEM SLOW RELEASE

1. Were you sent here from TROUBLESHOOTING? If so, go to next step. If not, go to «DIAGNOSTIC STARTING POINT - HYDRAULIC BRAKES»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__diagnostic-starting-point-hydraulic-brakes) under TROUBLESHOOTING.
2. Inspect the hydraulic brake system for proper operation. See «HYDRAULIC BRAKE SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__hydraulic-brake-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to step 5 . If not, go to next step.
3. Inspect the brake assist system for proper operation. See «BRAKE ASSIST SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-assist-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to step 5 . If not, go to next step.
4. Inspect the disc brake system for proper operation. See «DISC BRAKE SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__disc-brake-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to next step.
5. Road test the vehicle to confirm proper operation. See «BRAKE SYSTEM VEHICLE ROAD TEST»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under TROUBLE SHOOTING. Is the condition still present? If so, go to step 2 . If not, the system is okay.

BRAKE PULSATION

1. Were you sent here from TROUBLESHOOTING? If so, go to next step. If not, then see «DIAGNOSTIC STARTING POINT - HYDRAULIC BRAKES»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__diagnostic-starting-point-hydraulic-brakes) under TROUBLESHOOTING.
2. Inspect the suspension system for proper operation. Did you find and correct a condition? If so, go to step 6 . If not, go to next step.
3. Inspect the anti-lock brake system for proper operation. Did you find and correct a condition? If so, go to step 6 . If not, go to next step.
4. Inspect the disc brake system for proper operation. See «DISC BRAKE SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__disc-brake-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to step 6 . If not, go to next step.
5. Inspect the hydraulic brake system for proper operation. See «HYDRAULIC BRAKE SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__hydraulic-brake-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to next step. If not, then see «DIAGNOSTIC STARTING POINT - HYDRAULIC BRAKES»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__diagnostic-starting-point-hydraulic-brakes) under TROUBLE SHOOTING.
6. Road test the vehicle in order to confirm proper operation. See «BRAKE SYSTEM VEHICLE ROAD TEST»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under TROUBLE SHOOTING. Is the condition still present? If so, go to step 2 . If not, the repair is complete.

BRAKE SYSTEM NOISE

1. Were you sent here from TROUBLESHOOTING? If so, go to next step. If not, go to «DIAGNOSTIC STARTING POINT - HYDRAULIC BRAKES»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__diagnostic-starting-point-hydraulic-brakes) under TROUBLESHOOTING.
2. Inspect the disc brake system for proper operation. See «DISC BRAKE SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__disc-brake-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to step 6 . If not, go to next step.
3. Inspect the brake assist system for proper operation. See «BRAKE ASSIST SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-assist-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to step 6 . If not, go to next step.
4. Inspect the hydraulic brake system for proper operation. See «HYDRAULIC BRAKE SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__hydraulic-brake-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to step 6 . If not, go to next step.
5. Inspect the park brake system for proper operation. See «PARK BRAKE SYSTEM TESTING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__park-brake-system-testing) under SYSTEM TESTING. Did you find and correct a condition? If so, go to next step. If not, go to «DIAGNOSTIC STARTING POINT - HYDRAULIC BRAKES»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__diagnostic-starting-point-hydraulic-brakes) under TROUBLE SHOOTING.
6. Road test the vehicle in order to confirm proper operation. See «BRAKE SYSTEM VEHICLE ROAD TEST»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under TROUBLE SHOOTING. Is the condition still present? If so, go to step 2 . If not, the system should be okay.

BRAKE WARNING INDICATOR ALWAYS ON

1. Did you perform the Hydraulic Brake Diagnostic System Check? If so, go to next step. If not, go to «DIAGNOSTIC STARTING POINT - HYDRAULIC BRAKES»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__diagnostic-starting-point-hydraulic-brakes) under TROUBLESHOOTING.
2. Inspect the brake fluid level. Is the brake fluid level okay? If so, go to next step. If not, go to «BRAKE FLUID LOSS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-fluid-loss) .
3. Turn ON the ignition, with the engine OFF. Release the park brake. With a scan tool, observe the PARK BRAKE SWITCH parameter in the Instrument Panel Cluster data list. Does the scan tool indicate that the PARK BRAKE SWITCH parameter is Off? If so, go to next step. If not, go to step 5 .
4. With a scan tool, observe the LOW BRAKE FLUID parameter in the Instrument Panel Cluster data list. Does the scan tool indicate that the LOW BRAKE FLUID parameter is Off? If so, check for intermittent connections. If not, go to 6 .
5. Turn OFF the ignition. Disconnect the park brake switch. Turn ON the ignition, with the engine OFF. With a scan tool, observe the PARK BRAKE SWITCH parameter. Does the scan tool indicate that the PARK BRAKE SWITCH parameter is Off? If so, go to step 9 . If not, go to 7 .
6. Turn OFF the ignition. Disconnect the brake fluid level switch. Turn ON the ignition, with the engine OFF. With a scan tool, observe the LOW BRAKE FLUID parameter. Does the scan tool indicate that the LOW BRAKE FLUID parameter is Off? If so, go to step 10 . If not, go to step 8 .
7. Test the signal circuit of the park brake switch for a short to ground. Did you find and correct the condition? If so, go to step 15 . If not, go to step 11 .
8. Test the signal circuit of the brake fluid level switch for a short to ground. Did you find and correct the condition? If so, go to step 15 . If not, go to step 11 .
9. Inspect for poor connections at the harness connector of the park brake switch. Did you find and correct the condition? If so, go to step 15 . If not, go to step 13 .
10. Inspect for poor connections at the harness connector of the brake fluid level switch. Did you find and correct the condition? If so, go to step 15 . If not, go to step 13 .
11. Inspect for poor connections at the harness connector of the instrument cluster (IPC). Did you find and correct the condition? If so, go to step 15 . If not, go to 14 .
12. Replace the park brake switch. See «PARK BRAKE WARNING LAMP SWITCH»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. After repairs are complete, go to step 15 .
13. Replace the brake fluid level switch. See «MASTER CYLINDER FLUID LEVEL SENSOR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. After repairs are complete, go to step 15 .
14. Replace the Instrument Panel Cluster (IPC). See appropriate INSTRUMENT PANEL article in ACCESSORIES & EQUIPMENT. After repairs are complete, go to next step.
15. Operate the system in order to verify the repair. Did you correct the condition? If so, system is okay. If not, go to 2 .

BRAKE WARNING INDICATOR INOPERATIVE

1. Did you perform the Hydraulic Brake Diagnostic System Check? If so, go to next step. If not, go to «DIAGNOSTIC SYSTEM CHECK - HYDRAULIC BRAKES»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__diagnostic-system-check-hydraulic-brakes) under TROUBLE SHOOTING.
2. Turn OFF the ignition. Turn ON the ignition, with the engine OFF. Observe the Red Brake indicator. Does the Red Brake indicator illuminate briefly during the displays test? If so, go to next step. If not, go to step 11 .
3. Apply the park brake. Does the Red Brake indicator illuminate? If so, go to next step. If not, go to step 5 .
4. Turn OFF the ignition. Release the park brake. Disconnect the brake fluid level switch. Connect a 3-amp fused jumper wire between the signal circuit of the brake fluid level switch and the ground circuit of the brake fluid level switch. Turn ON the ignition, with the engine OFF. Does the Red Brake indicator illuminate? If so, go to step 10 . If not, go to step 7 .
5. Turn OFF the ignition. Disconnect the park brake switch. Connect a 3-amp fused jumper wire between the signal circuit of the park brake switch and a good ground. Turn ON the ignition, with the engine OFF. Does the Red Brake indicator illuminate? If so, go to step 9 . If not, go to next step.
6. Test the signal circuit of the park brake switch for a high resistance or a open. Did you find and correct the condition? If so, go to step 15 . If not, go to step 11 .
7. Test the signal circuit of the brake fluid level switch for a high resistance or a open. Did you find and correct the condition? If so, go to step 15 . If not, go to next step.
8. Test the ground circuit of the brake fluid level switch for a high resistance or an open. Did you find and correct the condition? If so, go to step 15 . If not, go to step 11 .
9. Inspect for poor case ground or poor connections at the harness connector of the park brake switch. Did you find and correct the condition? If so, go to step 15 . If not, go to step 12 .
10. Inspect for poor connections at the harness connector of the brake fluid level switch. Did you find and correct the condition? If so, go to step 15 . If not, go to step 13 .
11. Inspect for poor connections at the harness connector of the IPC. Did you find and correct the condition? If so, go to step 15 . If not, go to step 14 .
12. Replace the park brake switch. See «PARK BRAKE WARNING LAMP SWITCH»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. After repairs are complete, go to step 15 .
13. Replace the brake fluid level switch. See «MASTER CYLINDER FLUID LEVEL SENSOR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. After repairs are complete, go to step 15 .
14. Replace the Instrument Panel Cluster (IPC). See INSTRUMENT PANEL article. After repairs are complete, go to next step.
15. Operate the vehicle in order to verify the repair. Did you correct the condition? If so, system is okay. If not, go to step 2 .

BRAKE ASSIST SYSTEM TESTING

1. Were you sent here from a Brake Symptom table? If so, go to next step. If not, go to «DIAGNOSTIC STARTING POINT - HYDRAULIC BRAKES»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__diagnostic-starting-point-hydraulic-brakes) under TROUBLESHOOTING.
2. Inspect for proper brake pedal travel. See «BRAKE PEDAL TRAVEL»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under ADJUSTMENTS & INSPECTION. Is the brake pedal travel distance within the acceptable limits? If so, go to step 5 . If not, go to next step.
3. Inspect for worn, missing, misaligned, bent or damaged brake pedal system components. For the brake pedal pushrod component inspection, see «BRAKE PEDAL PUSHROD»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under ADJUSTMENTS & INSPECTION. Inspect the brake pedal bushings for excessive wear and/or damage and inspect the brake pedal for a misaligned, bent and/or damaged condition. Replace the brake pedal system components that are worn, missing, misaligned, bent or damaged. Refer to the following procedures as necessary. «BRAKE PEDAL ASSEMBLY»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. «VACUUM BRAKE BOOSTER»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION - for a bent or damaged pedal pushrod. Did you find and replace any worn, missing, misaligned, bent or damaged brake pedal system components? If so, go to next step. If not, go to step 5 .
4. Reinspect for proper brake pedal travel. See «BRAKE PEDAL TRAVEL»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under ADJUSTMENTS & INSPECTION. Is the brake pedal travel distance within the acceptable limits? If so, go to step 8 . If not, go to next step.
5. Check the engine vacuum source that supplies vacuum to the vacuum brake booster. See «BRAKE SYSTEM VACUUM SOURCE TEST»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-system-vacuum-source-test) under ADJUSTMENTS & INSPECTION. Is the vacuum reading within the acceptable limits? If so, go to next step. If not, repair cause of poor engine vacuum.
6. During the vacuum source inspection, did the vacuum booster check valve operate properly? If so, go to step 8 . If not, go to next step.
7. Replace the vacuum booster check valve. See «VACUUM BRAKE BOOSTER CHECK VALVE AND/OR HOSE»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. After completing the replacement, go next step.
8. Pump the brake pedal several times until the brake pedal effort increases significantly. Maintain moderate foot pressure on the brake pedal and start the engine. Observe pedal operation. Did the brake pedal drop slightly, then remain firm after the engine was started? If so, go to next step. If not, go to step 12 .
9. Release the brake pedal. Turn the ignition OFF, then wait 15 seconds. Pump the brake pedal 2 times to check for vacuum booster available vacuum reserve. Observe pedal effort. If operating properly, the vacuum brake booster should maintain assist for at least 2 pedal applications. Did the brake pedal effort increase significantly? If so, go to step 12 . If not, go to next step.
10. Inspect the brake pedal pushrod and the brake pedal for misalignment, a bent condition and/or damage. Is the brake pedal pushrod and/or the brake pedal misaligned, bent or damaged? If so, go to next step. If not, go to step 13 .
11. Replace the brake pedal pushrod and/or the brake pedal, as necessary. Refer to the following procedures: «BRAKE PEDAL ASSEMBLY»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. «VACUUM BRAKE BOOSTER»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION - for a bent or damaged pedal pushrod replacement. After repairs are complete, go to step 13 .
12. Replace the vacuum brake booster. See «VACUUM BRAKE BOOSTER»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. After repairs are complete, go to next step.
13. Install or connect any components that were removed or disconnected during diagnosis. After completing the operation, the brake system should be okay.

DISC BRAKE SYSTEM TESTING

1. Were you sent here from TROUBLESHOOTING? If so, go to next step. If not, go to «DIAGNOSTIC STARTING POINT - HYDRAULIC BRAKES»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__diagnostic-starting-point-hydraulic-brakes) under TROUBLESHOOTING.
2. Visually inspect the disc brake pads for the following conditions: See «BRAKE PAD»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-pad-inspection) under ADJUSTMENTS & INSPECTION. Lining thickness below specifications. Uneven and/or abnormal wear - edge-to-edge and/or side-to-side. Evidence of contamination from an external substance. Looseness or damage - including pad hardware. Did you find any conditions to indicate a concern with any of the front and/or rear disc brake pads? If so, go to next step. If not, go to step 12 .
3. Are any of the front and/or rear disc brake pads contaminated? If so, go to step 8 . If not, go to next step.
4. Are any of the front and/or rear disc brake pads worn unevenly? If so, go to step 7 . If not, go to next step.
5. Are any of the front and/or rear disc brake pads and/or pad hardware loose or damaged? If so, go to step 7 . If not, go to next step.
6. Remove and inspect the worn disc brake pads for glazing, looseness, heat spots or damage. Replace the worn disc brake pads as a complete axle set. See «BRAKE PADS - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) and/or «BRAKE PADS - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. After repairs are complete, go to step 12 .
7. Remove the front and/or rear disc brake calipers, as appropriate, from the mounting brackets and support the calipers. DO NOT disconnect the hydraulic brake flexible hoses from the calipers. See «BRAKE CALIPER - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-front) and/or «BRAKE CALIPER - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-rear) under REMOVAL & INSTALLATION. Inspect the disc brake caliper mounting bracket and the mounting/sliding hardware for the following conditions: See «DISC BRAKE MOUNTING & HARDWARE - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__disc-brake-mounting-hardware) and/or «DISC BRAKE MOUNTING & HARDWARE - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__disc-brake-mounting-hardware) under ADJUSTMENTS & INSPECTION. Loose, bent, cracked, or damaged caliper mounting bracket. Binding or seized hardware. Worn, damaged or missing hardware components. Replace components as required. Refer to the following procedures in REMOVAL & INSTALLATION, as required: «BRAKE CALIPER BRACKET - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) «BRAKE CALIPER BRACKET - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) «DISC BRAKE HARDWARE - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) «DISC BRAKE HARDWARE - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) Replace the unevenly-worn, loose or damaged disc brake pads as a complete axle set. See «BRAKE PADS - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) and/or «BRAKE PADS - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. After completing the inspection and replacement, go to step 12 .
8. Inspect the disc brake calipers, brake hoses and brake pipes for evidence of an external brake fluid leak. Replace any components found to be leaking brake fluid. Refer to the following procedures as required: «BRAKE CALIPER - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under OVERHAUL or «BRAKE CALIPER - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-front) under REMOVAL & INSTALLATION. «BRAKE CALIPER - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) or «BRAKE CALIPER - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-rear) under REMOVAL & INSTALLATION. «BRAKE HOSE - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. «BRAKE HOSE - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. «BRAKE PIPE»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-pipe) under REMOVAL & INSTALLATION. Did you find and correct the source of the leak causing contamination of the pads? If so, go to step 11 . If not, go to next step.
9. Inspect the wheel drive shaft outer seals for damage and evidence of a grease leak. Replace any wheel drive shaft seal that is found to be leaking grease which may be the source of the contamination to the pads. See FWD AXLE SHAFTS - BONNEVILLE & LESABRE article in DRIVE AXLES. Did you find and correct the source of the leak causing contamination of the pads? If so, go to step 11 . If not, go to next step.
10. Inspect the following systems for damage and evidence of an external fluid leak. Replace any components found to be leaking fluid which may be the source of the contamination to the pads. Refer to the following procedures: TROUBLESHOOTING in appropriate POWER RACK & PINION article in STEERING. TROUBLESHOOTING in appropriate AUTOMATIC TRANSMISSION article. After you find and correct the source of the leak causing contamination of the pads, go to next step.
11. Clean the remaining disc brake system components to remove any traces of the contaminant. Remove the front and/or rear disc brake calipers, as appropriate, from the mounting brackets and support the calipers. DO NOT disconnect the hydraulic brake flexible hoses from the calipers. See «BRAKE CALIPER - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-front) and/or «BRAKE CALIPER - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-rear) under REMOVAL & INSTALLATION. Inspect the disc brake caliper mounting/sliding hardware for the following conditions: See «DISC BRAKE MOUNTING & HARDWARE - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__disc-brake-mounting-hardware) and/or «DISC BRAKE MOUNTING & HARDWARE - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__disc-brake-mounting-hardware) under ADJUSTMENTS & INSPECTION. Binding or seized hardware. Distorted, worn, damaged or missing hardware components. Replace the caliper mounting/sliding hardware components as required. See «DISC BRAKE HARDWARE - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) and/or «DISC BRAKE HARDWARE - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. Replace the contaminated disc brake pads as a complete axle set. See «BRAKE PADS - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) and/or «BRAKE PADS - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. After completing the cleaning, inspection and replacement, go to next step.
12. Visually inspect each of the rear disc brake rotor shields/backing plates for evidence of contact with the brake rotors. Are any of the rear brake rotor shields/backing plates contacting the brake rotors? If so, go to next step. If not, go to step 14 .
13. Repair or replace the rear disc brake rotor shields/backing plates as required. See appropriate REAR SUSPENSION article in SUSPENSION. After completing the repair or replacement, go to next step.
14. Check the thickness of each of the disc brake rotors. NOTE: Make the following determination and answer the question individually for each rotor. Make a determination for each brake rotor if the rotor can be refinished and remain above the minimum requirements. See «BRAKE ROTOR THICKNESS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-rotor-thickness) under ADJUSTMENTS & INSPECTION. Does the disc brake rotor meet the minimum requirements for REFINISHING? If so, go to next step. If not, go to step 17 .
15. Inspect each of the disc brake rotors for the following surface and wear conditions: See «BRAKE ROTOR SURFACE & WEAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-rotor-surface-wear) under ADJUSTMENTS & INSPECTION. Braking Surface Conditions: Heavy rust and/or pitting. Cracks and/or heat spots. Excessive blueing discoloration. Braking Surface Wear Conditions: Deep or excessive scoring beyond maximum acceptable level. Lateral runout beyond maximum acceptable level. Thickness variation beyond maximum acceptable level. NOTE: Make the following determination and answer the question individually for each rotor. Make a determination for each brake rotor if the rotor requires refinishing based upon the results of the inspection. If the brake rotor exhibits any of the following conditions, it requires refinishing. Rotor exhibits one or more of the Braking Surface Conditions listed previously. Rotor is beyond the acceptable level in one or more of the Braking Surface Wear Conditions listed previously. Does the brake rotor require REFINISHING? If so, go to next step. If not, go to step 20 .
16. Refinish the brake rotor. See «BRAKE ROTOR REFINISHING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-rotor-refinishing) under REMOVAL & INSTALLATION. Inspect the brake rotor thickness. See «BRAKE ROTOR THICKNESS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-rotor-thickness) under ADJUSTMENTS & INSPECTION. Were you able to REFINISH the brake rotor within the minimum requirements? If so, go to step 20 . If not, go to step 19 .
17. Is the brake rotor at or below the DISCARD requirements? If so, go to step 19 . If not, go to next step.
18. Inspect each of the disc brake rotors for the following surface and wear conditions: See «BRAKE ROTOR SURFACE & WEAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-rotor-surface-wear) under ADJUSTMENTS & INSPECTION. Braking Surface Conditions: Heavy rust and/or pitting. Cracks and/or heat spots. Excessive blueing discoloration. Braking Surface Wear Conditions: Deep or excessive scoring beyond maximum acceptable level. Lateral runout beyond maximum acceptable level. Thickness variation beyond maximum acceptable level. NOTE: Make the following determination and answer the question individually for each rotor. Make a determination for each brake rotor if the rotor requires replacement based upon the results of the inspection. If a brake rotor exhibits any of the following conditions, it requires replacement. Rotor exhibits one or more of the Braking Surface Conditions listed previously. Rotor is beyond the acceptable level in one or more of the Braking Surface Wear Conditions listed previously. Does the brake rotor require replacement? If so, go to next step. If not, go to step 20 .
19. Replace the brake rotor. See «BRAKE ROTOR - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-rotor-front) or «BRAKE ROTOR - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. After repairs are complete, go to next step.
20. Install or connect components that were removed or disconnected during diagnosis. After completing the operation the system should be okay.

HYDRAULIC BRAKE SYSTEM TESTING

1. Were you sent here from TROUBLESHOOTING? If so, go to next step. If not, go to «DIAGNOSTIC SYSTEM CHECK - HYDRAULIC BRAKES»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__diagnostic-system-check-hydraulic-brakes) under TROUBLESHOOTING.
2. Inspect and adjust the brake fluid level in the brake master cylinder. See «MASTER CYLINDER RESERVOIR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under BLEEDING BRAKE SYSTEM. Was the brake fluid level low? If so, go to next step. If not, go to step 4 .
3. Inspect the brake fluid for the following conditions, indicating brake fluid contamination: Fluid separation, indicating 2 types of fluid are present: Swirled appearance - oil-based substance. Layered appearance - silicone-based substance. Fluid discoloration: Cloudy appearance - moisture. Dark appearance/suspended particles in fluid - dirt, rust, corrosion, brake dust. Inspect the master cylinder reservoir cap diaphragm and the reservoir-to-master cylinder grommets for swelling, indicating fluid contamination. Do any of the above conditions exist? If so, go to step 5 . If not, go to step 6 .
4. Inspect the brake fluid for the following conditions, indicating brake fluid contamination: Fluid separation, indicating 2 types of fluid are present: Swirled appearance - oil-based substance. Layered appearance - silicone-based substance. Fluid discoloration: Cloudy appearance - moisture. Dark appearance/suspended particles in fluid - dirt, rust, corrosion, brake dust. Inspect the master cylinder reservoir cap diaphragm and the reservoir-to-master cylinder grommets for swelling, indicating fluid contamination. Do any of the above conditions exist? If so, go to next step. If not, go to step 12 .
5. Flush the hydraulic brake system. See «HYDRAULIC BRAKE SYSTEM FLUSHING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__hydraulic-brake-system-flushing) under BLEEDING BRAKE SYSTEM. If the brake fluid WAS contaminated with an oil-based or a silicone-based fluid, indicated by fluid separation and/or a swollen master cylinder reservoir cap diaphragm and/or swollen reservoir-to-master cylinder grommets, perform the following steps. Refer to the procedures indicated. Remove ALL of the following components listed. Each component contains internal rubber seals/linings which have been contaminated. Clean out the hydraulic brake pipes using denatured alcohol, or equivalent. Dry the brake pipes using non-lubricated, filtered air. Repair or replace ALL of the following components listed. Each component contains internal rubber seals/linings which have been contaminated: «MASTER CYLINDER»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under OVERHAUL or «MASTER CYLINDER»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION Brake master cylinder reservoir: Clean the brake master cylinder reservoir using denatured alcohol, or equivalent, then dry the reservoir using non-lubricated, filtered air, or if necessary, replace the brake master cylinder reservoir. Replace the brake master cylinder reservoir cap diaphragm. «BRAKE HOSE - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. «BRAKE HOSE - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. «BRAKE CALIPER - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under OVERHAUL or «BRAKE CALIPER - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-front) under REMOVAL & INSTALLATION. «BRAKE CALIPER - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-rear) under REMOVAL & INSTALLATION. Brake Pressure Modulator Valve (BPMV) Replacement in appropriate ANTI-LOCK article in BRAKES. If the brake fluid was NOT contaminated with an oil-based fluid, but WAS contaminated with water or dirt, rust, corrosion, and/or brake dust, replace the brake master cylinder reservoir cap diaphragm which may have allowed moisture or dirt to enter the system. Refill and bleed the hydraulic brake system. See «HYDRAULIC BRAKE SYSTEM BLEEDING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under BLEEDING BRAKE SYSTEM. After completing the operation and any required repairs and/or replacements, go to step 9 .
6. Inspect the following hydraulic brake system components for external fluid leaks. Repair or replace any of the components found to be leaking brake fluid. Refer to the appropriate procedures: «MASTER CYLINDER»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under OVERHAUL or «MASTER CYLINDER»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION Brake master cylinder reservoir cap diaphragm. «BRAKE HOSE - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. «BRAKE HOSE - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. «BRAKE PIPE»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-pipe) under REMOVAL & INSTALLATION. «BRAKE CALIPER - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under OVERHAUL or «BRAKE CALIPER - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-front) under REMOVAL & INSTALLATION. «BRAKE CALIPER - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under OVERHAUL or «BRAKE CALIPER - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-rear) under REMOVAL & INSTALLATION. Brake Pressure Modulator Valve (BPMV) Replacement in appropriate ANTI-LOCK article in BRAKES. If you repaired or replaced any of the brake system components listed, bleed the hydraulic brake system. See «HYDRAULIC BRAKE SYSTEM BLEEDING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under BLEEDING BRAKE SYSTEM. While bleeding the hydraulic brake system, observe for the following conditions: The presence of air in the system at a bleeder valve location other than at the repair location, except if the brake master cylinder was replaced. An unrestricted and even flow of brake fluid per axle during the bleeding procedure. Did you find and correct a condition? If so, go to next step. If not, go to step 12 .
7. Was there air in the system at a bleeder valve location other than at the repair location, except if the brake master cylinder was replaced? If so, go to step 19 . If not, go to next step.
8. Was the flow of brake fluid unrestricted and even per axle during the bleeding procedure? If so, go to next step. If not, go to step 10 .
9. Inspect the hydraulic function of the brake calipers for proper operation. See «HYDRAULIC BRAKE COMPONENT OPERATION VISUAL INSPECTION»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__hydraulic-brake-component-operation-visual-inspection) under ADJUSTMENTS & INSPECTION. Was the hydraulic function of the brake calipers operating properly? If so, go to step 21 . If not, go to step 14 .
10. Was the flow of brake fluid restricted or uneven through front axle hydraulic components during the bleeding procedure? If so, go to step 13 . If not, go to next step.
11. Was the flow of brake fluid restricted or uneven through rear axle hydraulic components during the bleeding procedure? If so, go to step 17 .
12. Inspect the hydraulic function of the brake calipers for proper operation. See «HYDRAULIC BRAKE COMPONENT OPERATION VISUAL INSPECTION»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__hydraulic-brake-component-operation-visual-inspection) under ADJUSTMENTS & INSPECTION. Was the hydraulic function of the brake calipers operating properly? If so, go to step 15 . If not, go to next step.
13. Determine if the brake caliper is restricting the flow of brake fluid and/or not operating properly: Raise and support the vehicle. Remove the tire and wheel assemblies. Open the suspected caliper bleeder valve. Using a large C-clamp, compress the caliper piston and observe for an unrestricted flow of brake fluid and for free movement of the caliper piston. Close the caliper bleeder valve. Was the flow of brake fluid unrestricted and did the caliper piston move freely? If so, go to step 17 . If not, go to next step.
14. Repair or replace any brake caliper that was not operating properly. Refer to the appropriate procedure: «BRAKE CALIPER - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under OVERHAUL or «BRAKE CALIPER - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-front) under REMOVAL & INSTALLATION. «BRAKE CALIPER - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under OVERHAUL or «BRAKE CALIPER - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-rear) under REMOVAL & INSTALLATION. After completing the repair and/or replacement, go to step 21 .
15. Bleed the hydraulic brake system to observe for the presence of air in the system and to observe for an unrestricted and even flow of brake fluid per axle during the bleeding procedure. See «HYDRAULIC BRAKE SYSTEM BLEEDING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under BLEEDING BRAKE SYSTEM. Was there air in the system? If so, go to step 19 . If not, go to next step.
16. Was the flow of brake fluid unrestricted and even per axle during the bleeding procedure? If so, go to step 21 . If not, go to next step.
17. Inspect the hydraulic brake pipes and flexible brake hoses for signs of a fluid restriction; such as being bent, kinked, pinched or damaged. See «BRAKE PIPE & HOSE»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under ADJUSTMENTS & INSPECTION. Replace any of the hydraulic brake pipes and/or flexible brake hoses found to be bent, kinked, pinched or damaged. Refer to the following procedures as necessary: «BRAKE HOSE - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. «BRAKE HOSE - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. «BRAKE PIPE»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-pipe) under REMOVAL & INSTALLATION. If none of the hydraulic brake pipes or flexible brake hoses were visibly bent, kinked, pinched or damaged, replace the hydraulic brake flex hose at the restricted location. Did you find and correct a condition? If so, go to step 21 . If not, go to next step.
18. Replace the brake pressure modulator valve (BPMV), in order to correct the hydraulic brake dynamic rear proportioning mechanical operation. Refer to Brake Pressure Modulator Valve (BPMV) Replacement in appropriate ANTI-LOCK article in BRAKES. After repairs are complete, go to step 21 .
19. Inspect the hydraulic brake system components for brake fluid seepage at a seal and/or fitting location, which may have drawn air into the system. Inspect the hydraulic brake system components for evidence of a recent repair, which may have introduced air into the system. Repair or replace any of the components found to be installed incorrectly or seeping brake fluid. Did you find and correct a condition? If so, go to step 21 . If not, go to next step.
20. Inspect the brake master cylinder for internal fluid leaks. See «BRAKE SYSTEM INTERNAL LEAK TEST»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under SYSTEM TESTING. Repair or replace the brake master cylinder if it is found to be leaking brake fluid internally. See «MASTER CYLINDER»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under OVERHAUL or «MASTER CYLINDER»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. Did you find and correct a condition? If so, go to next step.
21. Install or connect components that were removed or disconnected during diagnosis. After completing the operation, the system should be okay.

PARK BRAKE SYSTEM TESTING

1. Were you sent here from TROUBLESHOOTING? If so, go to step 3 . If not, go to next step.
2. Is the symptom related to the ability of the park brake system to hold and/or release? If so, go to «DIAGNOSTIC STARTING POINT-PARK BRAKE»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__diagnostic-starting-point-park-brake) . If not, go to «DIAGNOSTIC STARTING POINT - HYDRAULIC BRAKES»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__diagnostic-starting-point-hydraulic-brakes) .
3. Raise and support the vehicle with the rear axle supported by jack stands. With the park brake released, attempt to rotate the rear wheels to check the rear brakes for a significant amount of drag. Do the rear brakes have a significant amount of drag? If so, go to step 8 . If not, go to next step.
4. Apply the park brake. Attempt to rotate the rear wheels to check the rear brakes for a significant amount of drag. Do the rear brakes have a significant amount of drag? If so, go to next step. If not, go to step 6 .
5. Release the park brake. Rotate the rear wheels to check the rear brakes for a significant reduction in the amount of drag. Did the rear brakes exhibit a significant reduction in the amount of drag? If so, go to step 17 . If not, go to step 11 .
6. Visually inspect the park brake cable connections and the cables that are accessible on the underside of the vehicle for disconnections and/or damage. Were any of the park brake cables disconnected and/or damaged? If so, go to next step. In not, then go to step 8 .
7. Reconnect or replace the park brake cables as necessary. Refer to the following procedures as necessary: «PARK BRAKE PEDAL ASSEMBLY»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__park-brake-pedal-assembly) under REMOVAL & INSTALLATION The front park brake cable and the park brake pedal are replaced as an assembly. «PARK BRAKE CABLE - INTERMEDIATE»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. «PARK BRAKE CABLE - LEFT REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. «PARK BRAKE CABLE - RIGHT REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. After completing the repair and/or replacement, go to next step.
8. Remove the rear tire and wheel assemblies. Have an assistant apply and release the park brake while you observe both of the rear caliper apply levers and the rear park brake cables for free and complete motion during both apply and release. Did the caliper apply levers and the rear park brake cables exhibit free and complete motion during both apply and release of the park brake? If so, go to next step. If not, go to step 11 .
9. Cycle the park brake. Apply and release several times to adjust the caliper pistons. Apply the park brake. Attempt to rotate the rear wheels to check the rear brakes for a significant amount of drag. Do the rear brakes have a significant amount of drag? If so, go to next step. If not, go to step 11 .
10. Release the park brake. Rotate the rear wheels to check the rear brakes for a significant reduction in the amount of drag. Did the rear brakes exhibit a significant reduction in the amount of drag? If so, go to step 17 . If not, go to next step.
11. Disconnect the intermediate park brake cable from the front cable. See «PARK BRAKE CABLE - INTERMEDIATE»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. Disconnect the rear park brake cables from the caliper apply levers. See «PARK BRAKE CABLE - LEFT REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) and «PARK BRAKE CABLE - RIGHT REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. Inspect the intermediate and rear park brake cables for free movement. Using a wrench on each of the caliper piston apply lever bolts, apply and release the levers. Observe for a free return of the levers when released. Do any of the park brake cables checked require replacement? If so, go to step 13 . If not, go to next step.
12. Did the brake caliper apply levers return freely when released? If so, go to step 19 . If not, go to step 18 .
13. Replace any of the park brake cables inspected that do not have free movement. Refer to the following procedures: «PARK BRAKE CABLE - INTERMEDIATE»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. «PARK BRAKE CABLE - LEFT REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. «PARK BRAKE CABLE - RIGHT REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. After repairs are complete, go to next step.
14. Cycle the park brake. Apply and release several times to adjust the caliper pistons. Apply the park brake. Attempt to rotate the rear wheels to check the rear brakes for a significant amount of drag. Do the rear brakes have a significant amount of drag? If so, go to next step. If not, go to step 16 .
15. Release the park brake. Rotate the rear wheels to check the rear brakes for a significant reduction in the amount of drag. Did the rear brakes exhibit a significant reduction in the amount of drag? If so, go to step 17 . If not, go to next step.
16. Disconnect the intermediate park brake cable from the front cable. See «PARK BRAKE CABLE - INTERMEDIATE»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. Disconnect the rear park brake cables from the caliper apply levers. See «PARK BRAKE CABLE - LEFT REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) and «PARK BRAKE CABLE - RIGHT REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION. Using a wrench on the caliper piston apply lever bolt, cycle each caliper piston. Apply and release several times to adjust the caliper pistons. Have an assistant use a wrench on the caliper piston apply lever bolt to apply and maintain the caliper piston. Attempt to rotate the rear wheels to check the rear brakes for a significant amount of drag. Repeat steps D and E for the other side of the vehicle. Release the caliper piston apply levers. Rotate the rear wheels to check the rear brakes for a significant reduction of drag. Did the brake calipers apply and release properly? If so, go to next step. If not, go to step 18 .
17. Grasp the intermediate park brake cable and pull downward to check the amount of tension on the park brake cables. The park brake cables should have a moderate amount of tension. Quickly release the intermediate cable and observe for a quick and complete return of the cable. Did the park brake cables have a moderate amount of tension and exhibit a quick and complete return? If so, go to step 20 . If not, go to step 19 .
18. Replace the appropriate rear brake caliper. See «BRAKE CALIPER - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-rear) under REMOVAL & INSTALLATION. After repairs are complete, go to step 20 .
19. Replace the park brake pedal assembly. See «PARK BRAKE PEDAL ASSEMBLY»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__park-brake-pedal-assembly) under REMOVAL & INSTALLATION. After repairs are complete, go to next step.
20. Apply the park brake. Attempt to rotate the rear wheels to check the rear brakes for a significant amount of drag. Release the park brake. Rotate the rear wheels to check the rear brakes for a significant reduction of drag. Did the park brake apply and release properly? If so, go to next step. If not, go to step 3 .
21. Install or connect any components that were removed or disconnected during diagnosis. After completing the operation, the system should be okay.

1. In order to inspect for external brake fluid leaks, first check the fluid level in the master cylinder. While a slight brake fluid level drop can be considered a normal condition due to brake lining wear, a very low level may indicate a brake fluid leak in the hydraulic system.
2. If the fluid level is abnormally low, adjust the brake fluid level. See «MASTER CYLINDER RESERVOIR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under BLEEDING BRAKE SYSTEM.
3. Start the engine and allow it to idle.
4. Apply constant, moderate foot pressure to the brake pedal. If the brake pedal gradually falls away while under foot pressure, there may be a brake fluid leak.
5. Turn OFF the ignition.
6. Visually inspect the following brake system components for brake fluid leaks, excessive corrosion, and damage. Give particular attention to all brake pipe and flexible hose connections to ensure that there are not any slight brake fluid leaks - even though the brake pedal may feel firm and hold steady: Master cylinder brake pipe fittings. All brake pipe connections. Brake pipes. Brake hoses and connections. Brake calipers and/or wheel cylinders, if equipped.
7. While slight dampness around the master cylinder reservoir can be considered acceptable, brake fluid leaking from any of the brake system components requires immediate attention. If any of these components exhibit signs of brake fluid leakage, repair or replace those components. After the repair or replacement, reinspect the hydraulic brake system to assure proper function.

1. Start the engine and allow it to idle.
2. Apply light, steady pressure to the brake pedal. Observe both the brake pedal feel and travel.
3. Release the brakes and turn OFF the ignition.
4. If the brake pedal apply felt spongy, but the brake pedal travel was not excessive, perform the following steps: Inspect the brake system for external leaks. See «BRAKE SYSTEM EXTERNAL LEAK TEST»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) . Pressure bleed the brake system in order to purge any air that may be trapped in the system. See «HYDRAULIC BRAKE SYSTEM BLEEDING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) .
5. If the brake pedal apply did not feel spongy, but the brake pedal travel was excessive, perform the following steps: Loosen the master cylinder-to-brake power booster mounting nuts. Carefully pull the master cylinder away from the brake power booster just enough to inspect the mounting surface of the master cylinder. Inspect the master cylinder mounting surface at the primary piston for brake fluid leaks.
6. If the master cylinder exhibits any leakage around the primary piston, then the primary piston primary seal and/or secondary seal is leaking and the master cylinder requires overhaul or replacement.
7. If the master cylinder primary piston does not exhibit any leakage, pressure bleed the brake system. See «HYDRAULIC BRAKE SYSTEM BLEEDING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) .
8. If the brake pedal apply did not feel spongy, and the brake pedal travel was initially steady and not excessive, but then gradually fell, then the master cylinder requires overhaul or replacement due to an internal leak past the secondary piston from the secondary piston primary seal or secondary seal.
9. If the brake pedal apply did not feel spongy, and the brake pedal travel was initially steady and not excessive, then fell slightly, then became steady again, then the brake pressure modulator valve (BPMV) may be leaking internally, and may require replacement.

BRAKE SYSTEM VACUUM SOURCE TEST

1. Disconnect the engine vacuum hose from the vacuum brake booster check valve.
2. Install a vacuum gage to the engine vacuum hose.
3. Start the engine and allow the engine to idle until normal operating temperatures are reached.
4. Check to see if the engine vacuum reading is within the specified normal engine vacuum range. See «ENGINE VACUUM RANGE SPECIFICATION»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) table. ENGINE VACUUM RANGE SPECIFICATION Application In. Hg. (kPa) Normal Engine Vacuum Range 14-20 (47-68)
5. Turn the ignition OFF.
6. If the engine vacuum reading is within the specified normal range, proceed to step 10 . See «ENGINE VACUUM RANGE SPECIFICATION»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) table.
7. If the engine vacuum reading is NOT within the specified normal range, inspect the engine vacuum hose for the following conditions. Tight connection to the engine. Collapse, deformation or contamination. Cracks, cuts, dry-rot.
8. If any of these conditions were found with the engine vacuum hose, replace the hose, then repeat steps 2 - 4 .
9. If none of these conditions were found with the engine vacuum hose, then there is an engine vacuum source problem, check the engine vacuum system.
10. Remove the vacuum brake booster check valve from the booster.
11. Install the check valve to the engine vacuum hose.
12. Install the vacuum gage to the check valve.
13. Start the engine and allow the engine to idle until normal operating temperatures are reached.
14. Turn the ignition OFF.
15. Check to see if the engine vacuum reading is maintained within the specified normal engine vacuum range. See «ENGINE VACUUM RANGE SPECIFICATION»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) table.
16. If the engine vacuum reading is maintained within the specified normal range, proceed to step 18 .
17. If the engine vacuum reading is NOT maintained within the specified normal range, replace the brake booster check valve, then repeat steps 11 - 15 .
18. Inspect the brake booster check valve grommet for the following conditions. Firm connection to the vacuum brake booster. Deformation or contamination. Cracks, cuts, dry-rot.
19. If any of these conditions were found with the check valve grommet, replace the grommet.

BURNISHING PADS & ROTORS

Burnishing the brake pads and brake rotors is necessary in order to ensure that the braking surfaces are properly prepared after service has been performed on the disc brake system.

This procedure should be performed whenever the disc brake rotors have been refinished or replaced, and/or whenever the disc brake pads have been replaced.

1. Select a smooth road with little or no traffic.
2. Accelerate the vehicle to 30 MPH.
3. Using moderate to firm pressure, apply the brakes to bring the vehicle to a stop. DO NOT allow the brakes to lock. Use care to avoid overheating the brakes while performing this step.
4. Repeat steps 2 and 3 until approximately 20 stops have been completed. Allow sufficient cooling periods between stops in order to properly burnish the brake pads and rotors.

Removal

1. Inspect the fluid level in the brake master cylinder reservoir. If the brake fluid level is midway between the maximum-full point and the minimum allowable level, no brake fluid needs to be removed from the reservoir before proceeding.
2. If the brake fluid level is higher than midway between the maximum-full point and the minimum allowable level, remove brake fluid to the midway point before proceeding.
3. Raise the vehicle and suitably support. Remove the tire and wheel assembly.
4. Install a large C-clamp over the body of the brake caliper with the C-clamp ends against the rear of the caliper body and against the outer brake pad.
5. Tighten the C-clamp until the caliper piston is compressed into the caliper bore enough to allow the caliper to slide past the brake rotor. Remove the C-clamp from the caliper.
6. Remove the bottom brake caliper pin bolt. Pivot the brake caliper body upward and secure out of the way with heavy mechanic's wire or equivalent. DO NOT disconnect the hydraulic brake flexible hose from the caliper.
7. Install a large C-clamp over the body of the brake caliper with the C-clamp ends against the rear of the caliper body and against an old inner brake pad or a wood block installed against the caliper piston.
8. Tighten the C-clamp until the caliper piston is compressed completely into the caliper bore. Remove the C-clamp and the old brake pad or wood block from the caliper.
9. Remove the inboard and outboard brake pads from the brake caliper bracket. Remove and inspect the brake pad retainers.

Installation

1. Inspect the caliper bolt suspension boots for cuts, tears, or deterioration. If damaged, replace the pin boots. See «DISC BRAKE HARDWARE - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) .
2. Inspect the caliper pin bolts for damage or corrosion. Replace if damaged or corroded. DO NOT attempt to clean away corrosion. Corrosion is typically caused by damaged pin boots. See «DISC BRAKE HARDWARE - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) .
3. Inspect the caliper piston boot for deterioration, replace if damaged. See «BRAKE CALIPER - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under OVERHAUL.
4. Lubricate the front brake caliper pin bolts with a thin coat of NIGLUBE(R) grease. Install the brake pad retainers into the brake caliper bracket. Install both brake pads into the brake caliper bracket.
5. Pivot the brake caliper down over the brake pads and into the brake caliper bracket. Insert the lower brake caliper pin bolt and tighten it to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) .
6. Install the tire and wheel assembly. Lower the vehicle.
7. With the engine OFF, gradually apply the brake pedal to approximately 2/3 of its travel distance. Slowly release the brake pedal. Wait 15 seconds, then repeat until a firm brake pedal is obtained. This will properly seat the brake caliper pistons and brake pads.
8. Fill the brake master cylinder reservoir to the proper level. See «MASTER CYLINDER RESERVOIR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under BLEEDING BRAKE SYSTEM. Burnish the pads and rotors. See «BURNISHING PADS & ROTORS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__burnishing-pads-rotors) .

1. Inspect the fluid level in the brake master cylinder reservoir.
2. If the brake fluid level is midway between the maximum-full point and the minimum allowable level, no brake fluid needs to be removed from the reservoir before proceeding.
3. If the brake fluid level is higher than midway between the maximum-full point and the minimum allowable level, remove brake fluid to the midway point before proceeding.
4. Raise and support the vehicle. Remove the tire and wheel assembly. Install and hand tighten 2 wheel lug nuts to retain the rotor to the hub.
5. Install a large C-clamp over the body of the brake caliper with the C-clamp ends against the rear of the caliper body and against the outer brake pad. Tighten the C-clamp until the caliper piston is compressed into the caliper bore enough to allow the caliper to slide past the brake rotor. Remove the C-clamp from the caliper.
6. Remove the brake hose to caliper bolt from the brake caliper. Remove and discard the copper brake hose gaskets. These gaskets may be stuck to the brake caliper and/or the brake hose end. Plug the opening in the brake caliper and hose to prevent fluid loss and contamination.
7. Remove the caliper pin bolts. Note the location of the caliper pin bolts. Remove the caliper from the caliper bracket. Inspect the caliper pin bolt boots in the caliper bracket for the following conditions: Cuts Tears Deterioration Replace any damaged caliper pin bolt boots. See «DISC BRAKE HARDWARE - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) .

Note. DO NOT apply lubricant to the brake pad hardware.

1. If reusing the brake caliper pin bolts, wipe the old grease from the brake caliper pin bolts with a clean shop towel.
2. Apply a thin coat of NIGLUBE(R) grease to the brake caliper pin bolts. It is not necessary to apply lubricant to the brake pad hardware or the threads of the caliper pin bolts.
3. Install the brake caliper over the brake pads into the brake caliper bracket.
4. Install the caliper pin bolts. Tighten the brake caliper pin bolts to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) . Assemble the brake hose bolt and the NEW copper brake hose gaskets to the brake hose. Install the brake hose to caliper bolt to the brake caliper. Tighten the brake hose to caliper bolt to specification.
5. Bleed the brake system. See «HYDRAULIC BRAKE SYSTEM BLEEDING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under BLEEDING BRAKE SYSTEM.
6. With the engine OFF, gradually apply the brake pedal to approximately 2/3 of its travel distance. Slowly release the brake pedal. Wait 15 seconds, then repeat this step until a firm brake pedal is obtained. This will properly seat the brake caliper pistons and brake pads.
7. Remove the wheel lug nuts retaining the brake rotor to the hub. Install the tire and wheel assembly. Lower the vehicle.

Scheme 1

1. Remove the brake caliper from the mounting bracket and support the brake caliper with heavy mechanic's wire, or equivalent; DO NOT disconnect the hydraulic brake flexible hose from the caliper. See «BRAKE CALIPER - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-front) .
2. Remove the brake pads from the brake caliper bracket. Remove the brake pad retainers from the brake caliper bracket.
3. Remove the brake caliper bracket bolts. Remove the brake caliper bracket.
4. Use a wire brush to clean any debris or rust from the brake caliper bracket. Inspect the brake mounting and hardware. See «DISC BRAKE HARDWARE - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) .
5. Inspect the brake caliper bracket for cracks or damage. Replace the brake caliper bracket if cracked or damaged.

The caliper bracket bolts threads and the threaded holes of the caliper bracket must be free of threadlocker residue and debris prior to re-application of threadlocker in order to ensure proper adhesion and fastener retention.

1. Prepare the bolts and the threaded holes for assembly.
2. Thoroughly clean the residue from the fastener threads using denatured alcohol or equivalent and allow to dry.
3. Thoroughly clean the residue from the threaded holes using denatured alcohol or equivalent and allow to dry.
4. If reusing the old caliper bracket bolts, apply threadlocker (GM P/N 12345493), or equivalent to two-thirds of the threaded length of the fastener. Ensure that there are no gaps in the threadlocker along the length of the filled area of the fastener.
5. Allow the threadlocker to cure approximately 10 minutes before installation.

1. Install the brake caliper bracket to the steering knuckle. Install the brake caliper bracket bolts and tighten them to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) .
2. Lubricate the brake caliper pin bolts with a thin coat of NIGLUBE(R) grease. Install the brake pad retainers to the brake caliper bracket. Install the brake pads to the brake caliper bracket.
3. Install the brake caliper. See «BRAKE CALIPER - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-front) .

BRAKE ROTOR - FRONT

1. Remove the tire and wheel assembly.
2. Remove the brake caliper from the mounting bracket and support the brake caliper with heavy mechanic's wire, or equivalent; do NOT disconnect the hydraulic brake flexible hose from the caliper. See «BRAKE CALIPER - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-front) .
3. Remove the brake caliper bracket assembly. See «BRAKE CALIPER BRACKET - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) . Mark the relationship of the rotor to the hub. Remove the brake rotor.

Note. Whenever the rotor has been separated from the wheel bearing flange, clean any rust or contaminants from the wheel bearing flange and the brake rotor mating surfaces. Failure to do this may result in increased lateral runout of the brake rotor, and brake pulsation.

1. Use the Rotor Resurfacing Kit (J-41013) in order to thoroughly clean any corrosion from the wheel flange. Use the Wheel Hub Resurfacing Kit (J-42450-A) in order to clean any rust or corrosion from the wheel hub surface.
2. Install the brake rotor over the wheel studs onto the wheel bearing flange. Install the brake caliper bracket assembly. See «BRAKE CALIPER BRACKET - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) .
3. Install the brake caliper to the brake caliper bracket assembly. See «BRAKE CALIPER - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-front) . Install the tire and wheel assembly.

1. Raise and suitably support the vehicle. Remove the tire and wheel assembly.
2. Clean all dirt and foreign material from the brake hose and the brake pipe fittings.
3. Disconnect the brake pipe fitting from the brake hose, than cap or plug the brake pipe fitting end. Using a flat-bladed tool, remove the brake hose retainer from the brake hose. Remove the brake hose from the brake hose bracket.
4. Remove the brake hose to caliper bolt from the brake caliper. Remove the brake hose from the brake caliper. Remove and discard the 2 copper brake hose gaskets. These gaskets may be stuck to the brake caliper and/or the brake hose end.
5. Install a rubber cap or plug to the exposed brake pipe fitting end in order to prevent brake fluid loss and/or contamination. Install a rubber plug into the brake hose to caliper bolt hole of the brake caliper.
6. Remove the hose bracket bolt from the strut assembly and remove the hose.

1. Remove the rubber plug from the brake hose to caliper bolt hole of the brake caliper.
2. Assemble the brake hose, the NEW copper brake hose gaskets, and the brake hose bolt to the brake hose.
3. Install the brake hose to caliper bolt to the brake caliper. Tighten the brake hose to caliper bolt to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) .
4. Install the brake hose to the brake hose bracket. Install the brake hose retainer to the brake hose.
5. Remove the rubber cap or plug from the exposed brake pipe fitting end. Install the brake pipe fitting to the brake hose. Tighten the brake pipe fitting to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) .
6. Install the hose bracket and bolt to the strut assembly. Tighten the brake hose bracket bolt to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) .
7. Bleed the hydraulic brake system. See «HYDRAULIC BRAKE SYSTEM BLEEDING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under BLEEDING, FILLING & FLUSHING BRAKE SYSTEM. Install the tire and wheel assembly. Lower the vehicle.

1. Inspect the fluid level in the brake master cylinder reservoir.
2. If the brake fluid level is midway between the maximum-full point and the minimum allowable level, no brake fluid needs to be removed from the reservoir before proceeding.
3. If the brake fluid level is higher than midway between the maximum-full point and the minimum allowable level, remove brake fluid to the midway point before proceeding.
4. Raise the vehicle and suitably support. Remove the tire and wheel assembly.
5. Pull down on the front park brake cable. Remove the front park brake cable from the park brake cable connector.
6. Install a large C-clamp over the top of the brake caliper housing and against the back of the outboard brake pad. Compress the brake caliper piston into brake caliper bore to allow the piston enough clearance to slide the brake caliper off the brake rotor. Remove the C-clamp.
7. Remove brake hose to caliper bolt attaching the brake hose to the brake caliper. Remove the brake hose from the brake caliper. Remove and discard the 2 copper brake hose gaskets. These gaskets may be stuck to the brake caliper and/or the brake hose end. Be sure to plug the opening in the brake caliper and brake hose to prevent fluid loss and/or contamination.
8. Remove the park brake cable bracket from the brake caliper. Leave the park brake cable attached to the cable bracket. Disconnect the park brake cable from the park brake lever on the brake caliper.
9. Remove the lower brake caliper pin bolt. (Scheme 2) Rotate the brake caliper up. Remove the brake caliper from the upper brake caliper pin bolt.

1. If reusing the brake caliper retainers, clean the sleeves using denatured alcohol, or equivalent.
2. Lubricate the brake caliper pin bolts with a thin coat of high temperature silicone lube. Install the brake caliper to the upper caliper pin bolt. Rotate the brake caliper down over the brake pads into the brake caliper bracket. Install the brake caliper pin bolts and tighten them to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) .
3. Remove the plugs in the brake hose end. Assemble the brake hose bolt and the NEW copper brake hose gaskets to the brake hose. Install the brake hose to caliper bolt to the brake caliper. Tighten the brake hose to caliper bolt to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) .
4. Connect the park brake cable to the park brake lever on the brake caliper. Install the park brake cable bracket to the brake caliper. Tighten the park brake cable bracket bolt to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) . Install the front park brake cable to the park brake cable connector.
5. Bleed the brake system. See «HYDRAULIC BRAKE SYSTEM BLEEDING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) . With the engine OFF, gradually apply the brake pedal to approximately 2/3 of its travel distance. Slowly release the brake pedal. Wait 15 seconds, then repeat this step until a firm brake pedal is obtained. This will properly seat the brake caliper pistons and brake pads.
6. Install the tire and wheel assembly. Lower the vehicle.

1. Inspect the fluid level in the brake master cylinder reservoir. If the brake fluid level is midway between the maximum-full point and the minimum allowable level, no brake fluid needs to be removed from the reservoir before proceeding.
2. If the brake fluid level is higher than midway between the maximum-full point and the minimum allowable level, remove brake fluid to the midway point before proceeding.
3. Raise the vehicle and suitably support. Remove the tire and wheel assembly.
4. Using a large C clamp, compress the brake caliper piston into the brake caliper bore to gain enough clearance to allow the brake caliper to pivot off the brake caliper bracket. Compress the piston until resistance is felt, but no more than 0.039 in (1 mm) of piston travel. Exceeding this amount of piston travel will cause damage to the internal adjusting mechanism and/or the integral park brake mechanism.
5. Remove the park brake cable guide bolt from the lower control arm. Remove the bottom brake caliper pin bolt. Pivot the brake caliper body upward and secure out of the way with heavy mechanic's wire. DO NOT disconnect the hydraulic brake flexible hose from the caliper.
6. Remove the inboard and outboard brake pads from the brake caliper bracket. Remove and inspect the brake pad retainers.

1. Inspect the brake caliper bolt suspension boots for cuts, tears, or deterioration. If damaged, replace the brake caliper pin boots.
2. Inspect the brake caliper pin bolts for damage or corrosion. Replace if damaged or corroded. DO NOT attempt to clean away corrosion. Corrosion is typically caused by damaged pin boots. See «DISC BRAKE HARDWARE - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) .
3. Inspect the brake caliper piston boot for deterioration, repair or replace the brake caliper if damaged. See «BRAKE CALIPER - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-rear) .
4. Retract the brake caliper piston into the brake caliper bore. Use a spanner type wrench to turn the piston clockwise until it bottoms in the brake caliper bore and align the piston. Align the cutouts in the brake caliper piston to the alignment pins on the brake pads. Apply a thin coat of high temperature silicone lube to the rear brake caliper bolts.
5. Install the brake pad retainers into the brake caliper bracket. Install the inboard and outboard brake pads into the brake caliper bracket. Pivot the brake caliper down over the brake pads and into the brake caliper bracket. Insert the lower brake caliper pin bolt and tighten it to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) . Install the park brake cable guide bolt to the lower control arm and tighten it to specification.
6. Install the tire and wheel assembly. Lower the vehicle.
7. With the engine OFF, gradually apply the brake pedal to approximately 2/3 of its travel distance. Slowly release the brake pedal. Wait 15 seconds, then repeat until a firm brake pedal is obtained. This will properly seat the brake caliper pistons and brake pads.
8. Fill the brake master cylinder reservoir to the proper level. See «MASTER CYLINDER RESERVOIR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under BLEEDING BRAKE SYSTEM. Burnish the pads and rotors. See «BURNISHING PADS & ROTORS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__burnishing-pads-rotors) .

Scheme 2

1. Inspect the fluid level in the brake master cylinder reservoir. If the brake fluid level is midway between the maximum-full point and the minimum allowable level, no brake fluid needs to be removed from the reservoir before proceeding.
2. If the brake fluid level is higher than midway between the maximum-full point and the minimum allowable level, remove brake fluid to the midway point before proceeding.
3. Raise the vehicle and suitably support. Remove the tire and wheel assembly.
4. Pull down on the front park brake cable. Remove the front park brake cable from the park brake cable connector
5. Install a large C-clamp over the top of the brake caliper housing and against the back of the outboard brake pad. Compress the brake caliper piston into brake caliper bore to allow the piston enough clearance to slide the brake caliper off the brake rotor. Remove the C-clamp.
6. Remove brake hose to caliper bolt attaching the brake hose to the brake caliper.
7. Remove the brake hose from the brake caliper. Remove and discard the 2 copper brake hose gaskets. These gaskets may be stuck to the brake caliper and/or the brake hose end.
8. Remove the park brake cable bracket from the brake caliper. Leave the park brake cable attached to the cable bracket. Disconnect the park brake cable from the park brake lever on the brake caliper. Remove the lower brake caliper pin bolt. Rotate the brake caliper up. Remove the brake caliper from the upper brake caliper pin bolt.

1. If reusing the brake caliper retainers, clean the sleeves using denatured alcohol, or equivalent. Lubricate the brake caliper pin bolts with a thin coat of high temperature silicone lube.
2. Install the brake caliper to the upper caliper pin bolt. Rotate the brake caliper down over the brake pads into the brake caliper bracket.
3. Install the brake caliper pin bolts. Tighten to specifications. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) .
4. Remove the plugs in the brake hose end. Assemble the brake hose bolt and the NEW copper brake hose gaskets to the brake hose.
5. Install the brake hose to caliper bolt to the brake caliper. Tighten to specifications. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) .
6. Connect the park brake cable to the park brake lever on the brake caliper. Install the park brake cable bracket to the brake caliper. Tighten to specifications. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) .
7. Install the front park brake cable to the park brake cable connector. Bleed the brake system. See «BLEEDING BRAKE SYSTEM»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) .
8. With the engine OFF, gradually apply the brake pedal to approximately 2/3 of its travel distance.
9. Slowly release the brake pedal.
10. Wait 15 seconds, then repeat steps 9 - 10 until a firm brake pedal is obtained.
11. This will properly seat the brake caliper pistons and brake pads.
12. Install the tire and wheel assembly. Lower the vehicle.

1. Remove the brake caliper from the mounting bracket and support the brake caliper with heavy mechanic's wire, or equivalent. DO NOT disconnect the hydraulic brake flexible hose from the caliper. See «BRAKE CALIPER - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-rear) .
2. Remove the brake pads from the brake caliper bracket. Remove the brake pad retainers from the brake caliper bracket.
3. Remove the brake caliper bracket bolts. Remove the rear brake caliper bracket.
4. Use a wire brush to remove any rust and debris from the brake caliper bracket. Inspect the brake mounting and hardware. See «DISC BRAKE HARDWARE - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) . Inspect the brake caliper bracket. Replace the brake caliper bracket if cracked or damaged.

The caliper bracket bolts threads and the threaded holes of the caliper bracket must be free of threadlocker residue and debris prior to re-application of threadlocker in order to ensure proper adhesion and fastener retention.

1. Prepare the bolts and the threaded holes for assembly.
2. Thoroughly clean the residue from the fastener threads using denatured alcohol or equivalent and allow to dry.
3. Thoroughly clean the residue from the threaded holes using denatured alcohol or equivalent and allow to dry.
4. If reusing the old caliper bracket bolts, apply threadlocker (GM P/N 12345493), or equivalent to two-thirds of the threaded length of the fastener. Ensure that there are no gaps in the threadlocker along the length of the filled area of the fastener.
5. Allow the threadlocker to cure approximately 10 minutes before installation.

1. Install the brake caliper bracket. Install the brake caliper bracket bolts and tighten them to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) .
2. Lubricate the brake caliper pin bolts with a thin coat of high temperature silicone lube.
3. Install the brake pad retainers to the brake caliper bracket. Install the brake pads to the brake caliper bracket. Install the brake caliper. See «BRAKE CALIPER - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-rear) .

1. Remove the tire and wheel assembly.
2. Remove the brake caliper and bracket from the vehicle, support the caliper assembly away from the rotor. See «BRAKE CALIPER BRACKET - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) .
3. Mark the relationship of the rotor to the hub. Remove the brake rotor.

Note. Whenever the rotor has been separated from the wheel bearing flange, clean any rust or contaminants from the wheel bearing flange and the brake rotor mating surfaces. Failure to do this may result in increased lateral runout of the brake rotor, and brake pulsation.

1. Use the Rotor Resurfacing Kit (J-41013) in order to thoroughly clean any corrosion from the wheel flange. Use the Wheel Hub Resurfacing Kit (J-42450-A) in order to remove any rust or corrosion from the wheel hub surface.
2. Install the brake rotor over the wheel studs onto the wheel bearing flange. Install the brake caliper and bracket assembly. See «BRAKE CALIPER BRACKET - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) . Install the tire and wheel assembly.

1. Raise and suitably support the vehicle. Remove the tire and wheel assembly.
2. Clean all dirt and foreign material from the brake hose and the brake pipe fittings.
3. Disconnect the brake pipe fitting from the brake hose and cap or plug the brake pipe fitting end. Install a rubber cap or plug to the exposed brake pipe fitting end in order to prevent brake fluid loss and/or contamination.
4. Using a flat-bladed tool, remove the brake hose retainer from the brake hose. Remove the brake hose from the brake hose bracket.
5. Remove the brake hose to caliper bolt from the brake caliper. Remove the brake hose from the brake caliper.
6. Remove and discard the 2 copper brake hose gaskets. These gaskets may be stuck to the brake caliper and/or the brake hose end. Install a rubber cap or plug to the exposed brake pipe fitting end in order to prevent brake fluid loss and/or contamination.

1. Remove the rubber plug from the brake hose to caliper bolt hole of the brake caliper.
2. Assemble the brake hose, the NEW copper brake hose gaskets and the brake hose bolt to the brake hose. Install the brake hose to caliper bolt to the brake caliper. Tighten the brake hose to caliper bolt to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) .
3. Install the brake hose to the brake hose bracket. Install the brake hose retainer to the brake hose.
4. Remove the rubber cap or plug from the exposed brake pipe fitting end. Install the brake pipe fitting to the brake hose. Tighten the brake pipe fitting to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) .
5. Bleed the hydraulic brake system. See «HYDRAULIC BRAKE SYSTEM BLEEDING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) . Install the tire and wheel assembly. Lower the vehicle.

Removal (Bonneville)

1. Remove the I/P carrier assembly, to gain access to the brake pedal assembly bolts. See appropriate INSTRUMENT PANEL article in ACCESSORIES & EQUIPMENT.
2. Disconnect the accelerator cable from the accelerator pedal assembly.
3. Disconnect the electrical connectors from the stoplamp switch and the TCC/cruise control switch. Remove the stoplight switch from the pedal assembly. See «STOPLIGHT SWITCH»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) . Remove the TCC/cruise control release switch from the pedal assembly by rotating it counter-clockwise.
4. Remove the vacuum brake booster pushrod retainer from the clevis pin. Remove the foam spacer from the brake pedal clevis pin. Disconnect the vacuum brake booster push rod from the brake pedal clevis pin.
5. Remove the brake pedal assembly mounting to cowl stud nuts. Remove the brake pedal assembly mounting nuts from the booster studs. Remove the brake pedal assembly.

Installation (Bonneville)

1. Install the brake pedal assembly into position on the brake booster and cowl studs. Install the brake pedal assembly to brake booster mounting nuts and tighten them to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) . Install the brake pedal assembly to cowl stud mounting nuts and tighten them to specification.
2. Apply a small amount of lubricant, (GM P/N 12346293) or equivalent, to the clevis pin of the brake pedal. Connect the vacuum brake booster pushrod to the brake pedal clevis pin. Install the foam spacer to the brake pedal clevis pin. Install the retainer clip to the brake pedal clevis pin.
3. Install the TCC/cruise control release switch to the brake pedal assembly. Install the brake stoplight switch to the brake pedal assembly. See «STOPLIGHT SWITCH»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) . Connect the electrical connectors to the stoplight switch and the TCC/cruise control release switch.
4. Connect the accelerator cable to the accelerator pedal assembly. Install the IP assembly.

Removal (LeSabre)

1. Remove the IP carrier assembly, to gain access to the brake pedal assembly mounting nuts.
2. Remove the accelerator cable from the brake pedal bracket assembly. Remove the steering column support mounting nuts. See appropriate STEERING COLUMNS article in STEERING. Lower the steering column and support.
3. Disconnect the electrical connectors from the stoplight/ABS/shift lock switch. Remove the stoplamp/ABS/shift lock switch. See «STOPLIGHT SWITCH»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) . Disconnect the electrical connector from the TCC/cruise control release switch. Remove the TCC/cruise control release switch from the brake pedal assembly by rotating it counter-clockwise.
4. Remove the vacuum brake pushrod retainer from the brake pedal clevis pin. Remove the foam spacer from the brake pedal clevis pin. Disconnect the vacuum brake booster pushrod from the brake pedal.
5. Remove the brake pedal assembly mounting nuts from the booster studs. Remove the brake pedal assembly mounting to cowl stud nuts. Remove the brake pedal assembly.

Installation (LeSabre)

1. Install the brake pedal assembly into position on the brake booster and cowl studs. Install the brake pedal assembly to brake booster mounting nuts and tighten them to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) . Install the brake pedal assembly to cowl stud mounting nuts and tighten them to specification.
2. Apply a small amount of lubricant, GM P/N 12346293 or equivalent, to the clevis pin of the brake pedal. Connect the vacuum brake booster pushrod to the brake pedal clevis pin. Install the foam spacer to the brake pedal clevis pin. Install the retainer to the brake pedal clevis pin.
3. Install the TCC/cruise control release switch to the brake pedal assembly. Install the stoplight/ABS/shift lock switch. See «STOPLIGHT SWITCH»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) . Connect the electrical connectors to the stoplight/ABS/shift lock switch. Connect the electrical connector to the TCC/cruise control release switch.
4. Install the steering column. See appropriate STEERING COLUMNS article in STEERING. Install the accelerator cable to the brake pedal bracket assembly. Install the I/P assembly.

BRAKE PIPE

1. Obtain the correct size pipe and the correct size steel fitting nuts. Use the outside diameter of the pipe in order to specify the size. Cut the pipe square and to the correct length using a hack saw.
2. Measure the old pipe using a string and add 0.125" (3.2 mm) for each ISO flare.
3. Install the fittings before starting the flare.
4. Chamfer the inside and the outside diameter of the pipe using a de-burring tool.
5. Remove all traces of lubricant from the brake pipe and the ISO Flaring Kit (J-29803-A).
6. Clamp the flaring kit in a vise. (Scheme 3)
7. Select the correct size collet and forming mandrel for the pipe size used. Insert the properly formed mandrel into the flaring kit.
8. Hold the forming mandrel in place using your finger. Thread in the forcing screw until contact is made and the screw begins to move the forming mandrel.
9. Turn the forcing screw back one complete turn.
10. Slide the clamping nut over the brake pipe.
11. Insert the prepared brake pipe into the correct collet. Leave approximately 0.750" (19 mm) of tubing extending out of the collet. Insert the assembly into the flaring kit. Ensure that the brake pipe end contacts the face of the forming mandrel.
12. Tighten the clamping nut into the flaring kit body tightly in order to ensure that the pipe will not push out.
13. Wrench tighten the forcing screw until the screw bottoms.
14. Back the clamping nut out of the flaring kit.
15. Disassemble the clamping nut and the collet assembly.
16. Measure the flare diameter. It should fall between 0.272" and 0.286" (6.92 mm and 7.28 mm).
17. Use a tube bender in order to bend the new pipe to match the old pipe.
18. Maintain the following clearances: Maintain the minimum clearance of 0.75" (19 mm) to all moving components. Maintain the minimum clearance of 0.50" (13 mm) to all vibrating components. Maintain the minimum clearance of 0.25" (7 mm) to any shielded lines, unless clipped to a component.

Scheme 3

1. Remove the brake caliper from the mounting bracket and support the brake caliper with heavy mechanic's wire, or equivalent. Discard the old caliper pin bolts, new bolts are supplied in the hardware kit. It is not necessary to disconnect the hydraulic brake flexible hose from the caliper. See «BRAKE CALIPER - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-front) .
2. Remove the brake pads from the brake caliper bracket. Remove the brake pad retainers from the brake caliper bracket.
3. Remove the brake caliper bracket. See «BRAKE CALIPER BRACKET - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) .
4. Mount the brake caliper bracket in a vise. Using a flat bladed tool or punch carefully remove the caliper pin boots from brake caliper bracket and discard.
5. Wipe the old grease from the caliper pin bolts with a clean shop towel. Inspect the brake caliper bracket for cracks. If cracked, replace bracket.

1. Apply a thin coat of NIGLUBE(R) to the caliper guide pin. Install NEW caliper pin bolt boots to the caliper.
2. Install the brake caliper bracket. See «BRAKE CALIPER BRACKET - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) . Install the brake pad retainers to the caliper bracket. Install the brake pads to the caliper bracket.
3. Remove the heavy mechanics wire. Install the brake caliper. See «BRAKE CALIPER - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-front) .

1. Remove the brake caliper from the mounting bracket and support the brake caliper with heavy mechanic's wire, or equivalent; DO NOT disconnect the hydraulic brake flexible hose from the caliper. See «BRAKE CALIPER - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-rear) .
2. Remove the brake pads from the brake caliper bracket. Remove the brake pad retainers from the brake caliper bracket.
3. Remove the brake caliper bracket. See «BRAKE CALIPER BRACKET - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) .
4. Mount the brake caliper bracket in a vise. Clean all parts in clean, denatured alcohol. Dry with low pressure, non-lubricated, filtered air.
5. Inspect the brake caliper bracket for cracks. If cracked, replace bracket.

1. Lubricate the brake caliper pin bolt sleeves with a thin coat of high temperature silicone lube. Install the brake caliper bracket. See «BRAKE CALIPER BRACKET - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) .
2. Install the brake pad retainers to the bracket caliper bracket. Install the brake pads to the bracket caliper bracket.
3. Install the brake caliper to the brake caliper bracket. See «BRAKE CALIPER - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-rear) .

1. Disconnect the electrical connector from the brake fluid level sensor. Disconnect the brake pipes from the master cylinder.
2. Install a rubber cap or plug to the exposed brake pipe fitting end in order to prevent brake fluid loss and contamination.
3. Remove the 2 master cylinder mounting nuts. Remove the master cylinder. Remove the reservoir from the master cylinder if it is to be reused on a replacement master cylinder. See «MASTER CYLINDER RESERVOIR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) .

1. Install the brake master cylinder reservoir to the master cylinder if it was removed previously. See «MASTER CYLINDER RESERVOIR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) . Bench bleed the master cylinder. See «MASTER CYLINDER BENCH BLEEDING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__master-cylinder-bench-bleeding) under BLEEDING BRAKE SYSTEM.
2. Install the master cylinder to the vacuum brake booster. Install the 2 brake master cylinder mounting nuts and tighten them to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) .
3. Remove the plugs from the brake pipes. Install the brake pipes to the master cylinder. Tighten the brake pipe fittings at the master cylinder to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) .
4. Connect the electrical connector to the brake fluid level sensor. Bleed the hydraulic brake system. See «HYDRAULIC BRAKE SYSTEM BLEEDING»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) .

Disconnect the electrical connector from the brake fluid level sensor. Using a needle nose pliers carefully depress the retaining tabs on the end of the brake fluid level sensor and press the sensor through the reservoir to remove.

Align the brake fluid level sensor to the master cylinder reservoir. Press the brake fluid level sensor into the master cylinder reservoir. Connect the electrical connector to the brake fluid level sensor.

1. Remove the master cylinder from the vehicle. See «MASTER CYLINDER»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes). Remove the fluid level sensor. See «MASTER CYLINDER FLUID LEVEL SENSOR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes).
2. Drain the brake fluid from the master cylinder reservoir. Carefully tap out the reservoir retaining pins until clear of reservoir. (Scheme 4)
3. Remove the reservoir from the master cylinder. Remove the seals from the master cylinder reservoir.

1. Inspect the reservoir for cracks or deformities. If found, replace the reservoir. Clean the reservoir with clean denatured alcohol, or equivalent. Dry the reservoir with non-lubricated, filtered air.
2. Lubricate the new seals and the reservoir bayonets with NEW Delco Supreme 11(R), (GM P/N 12377967) or equivalent DOT-3 brake fluid. Install the seals, making sure they are fully seated.
3. Install the reservoir onto the master cylinder by pressing straight down by hand until pin holes are aligned. Carefully tap in the reservoir retaining pins to secure the reservoir.
4. Fill the master cylinder reservoir. See «MASTER CYLINDER RESERVOIR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under BLEEDING BRAKE SYSTEM. Install the brake fluid level sensor. See «MASTER CYLINDER FLUID LEVEL SENSOR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) . Install the master cylinder to the vehicle. See «MASTER CYLINDER»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) .

Scheme 4

1. Raise and support the vehicle.
2. Remove the front park brake cable from the cable guides.
3. Pull down on the intermediate park brake cable near the park brake connector.
4. Remove the intermediate park brake cable from the park brake cable connector.
5. Use the Parking Brake Cable Release Tool (J-37043) in order to disconnect the intermediate cable housing from the cable retaining bracket.
6. Disconnect the intermediate cable from the right rear park brake cable.
7. Disconnect the intermediate cable from the rear equalizer.
8. Remove the intermediate cable.

1. Connect the intermediate park brake cable to the equalizer.
2. Connect the right rear parking brake cable to the intermediate park brake cable.
3. Insert the intermediate park brake cable into the cable retaining bracket and lock the intermediate park brake cable into place.
4. Connect the front of the intermediate park brake cable to the park brake cable connector.
5. Install the front park brake cable to the cable guides.
6. Lower the vehicle.
7. To ensure that the park brake cable retainers are seated, cycle the park brake pedal 1 to 2 times.

1. Raise and support the vehicle. Remove the left rear tire and wheel assembly.
2. Remove the front park brake cable from the cable guides.
3. Pull down on the intermediate park brake cable near the park brake connector.
4. Disconnect the intermediate park brake cable from the park brake cable connector.
5. Disconnect the left rear park brake cable from the equalizer.
6. Remove the left park brake cable guide bolt.
7. Disconnect the left park brake cable from the park brake lever.
8. Use Parking Brake Cable Release Tool (J-37043) to depress the locking tabs on the left park brake cable.
9. Remove the left park brake cable from the caliper park brake cable bracket.
10. Use the parking brake cable release tool to depress the locking tabs on the left park brake cable.
11. Remove the left park brake cable from the rear support mounting bracket.

1. Install the left park brake cable to the park brake cable support bracket.
2. Press the left park brake cable into the park brake cable support bracket. Ensure that the locking tabs are properly seated.
3. Connect the left park brake cable to the park brake actuator lever.
4. Install the left park brake cable into the left brake caliper park brake cable bracket. Ensure that the locking tabs are properly seated.
5. Connect the left park brake cable to the equalizer.
6. Install the left park brake cable into the park brake cable guide.
7. Install the left park brake cable guide bolt and tighten it to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) .
8. Connect the intermediate park brake cable to the park brake cable connector.
9. Install the front park brake cable to the cable guides.
10. Install the tire and wheel assembly. Lower the vehicle.
11. To ensure that the park brake cable retainers are seated, cycle the park brake pedal 1 to 2 times.

1. Raise and support the vehicle. Remove the rear tire and wheel assembly.
2. Remove the front park brake cable from the cable guides.
3. Pull down on the intermediate park brake cable near the park brake cable connector.
4. Disconnect the intermediate park brake cable from the park brake connector.
5. Remove the right park brake cable guide bolt.
6. Disconnect the right rear park brake cable from the intermediate park brake cable connector.
7. Use the Parking Brake Cable Release Tool (J-37043) to depress the right brake cable locking tabs.
8. Remove the right park brake cable from the park brake cable support bracket.
9. Use the parking brake cable release tool to depress the right park brake cable locking tabs.
10. Remove the right park brake cable from the caliper park brake cable bracket.
11. Disconnect the right park brake cable from the park brake actuator lever.
12. Remove the right park brake cable from the vehicle.

1. Install the right park brake cable to the park brake cable support bracket.
2. Press the right park brake cable into the park brake cable support bracket. Ensure that the locking tabs are properly seated.
3. Connect the right park brake cable to the park brake actuator lever.
4. Install the right park brake cable to the caliper park brake cable bracket. Ensure that the locking tabs are properly seated.
5. Connect the intermediate park brake cable connector to the right park brake cable.
6. Pull down on the intermediate park brake cable near the park brake cable connector.
7. Connect the intermediate park brake cable to the park brake connector.
8. Install the right park brake cable into the park brake cable guide.
9. Install the right park brake cable guide bolt and tighten it to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) .
10. Install the front park brake cable to the cable guides.
11. Install the right tire and wheel assembly. Lower the vehicle.
12. To ensure that the park brake cable retainers are seated, cycle the park brake pedal 1 to 2 times.

PARK BRAKE PEDAL ASSEMBLY

Note. The automatic adjustment park brake pedal assembly and the front park brake cable are serviced as a unit.

1. Raise and suitably support the vehicle. Pull down on the intermediate park brake cable near the park brake connector.
2. Remove front park brake cable from the cable connector. Using Parking Brake Cable Release Tool (J-37043) remove the park brake cable from the cable support. Lower the vehicle.
3. Remove the fasteners at the rear edge of the insulator to disengage from the lower instrument panel. Pry out the retainers to release. Turn the heater temperature sensor 1/4 turn to release and allow to remain connected to its wire (CJ2 vehicles only). Disconnect the remaining electrical connectors as necessary.
4. Unsnap the carpet retainer and remove it from the floor. Pull the carpet back to expose park brake cable. Disconnect the electrical connector from the park brake warning lamp switch.
5. Remove the park brake lever assembly attaching nuts. (Scheme 5) Remove the park brake lever and cable assembly from the vehicle.

1. Install the park brake lever and cable assembly to the mounting studs. Install the park brake lever assembly attaching nuts and tighten them to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) .
2. Connect the electrical connector to the park brake warning lamp switch. Install the carpet and snap the carpet retainer into place.
3. Position and turn 1/4 turn to install the heater temperature sensor (CJ2 vehicles only). Connect the remaining electrical connectors.
4. Set the forward edge of the insulator onto the shelf of the dash mat. Align the insulator to the floor duct at the heating, ventilation and air conditioning module. Align the snap tab fasteners to the lower instrument panel and push upward to engage. Install the fasteners into the lower instrument panel and tighten them to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) .
5. Raise the vehicle. Connect the front park brake cable to the park brake cable connector on the Intermediate park brake cable. Lower the vehicle.
6. If a new park brake pedal assembly is being installed the cable tension set pin has to be removed. To set the park brake cable tension rotate the cable tension set pin 180 degrees and then pull down.

Scheme 5

1. Remove the left sound insulator panel. Disconnect the electrical connector from the park brake warning lamp switch.
2. Remove the park brake warning lamp switch retaining bolt. Remove the park brake warning lamp switch.

1. Install the park brake warning lamp switch to the park brake lever assembly. Align the alignment pin to locator hole. Install the park brake warning lamp switch retaining bolt and tighten it to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) .
2. Connect the electrical connector to the park brake warning lamp switch. Install the left sound insulator panel.

1. Remove the left sound insulator.
2. Rotate the stoplight/ABS/shift lock switch counterclockwise, then pull to remove the switch.
3. Disconnect the electrical connector from the switch.

Note. The stoplight switch is self adjusting when installed properly in the fully locked position. The twist lock type switch requires no further adjustment.

1. Install the stoplight switch into the retainer. Press the switch into the retainer until the switch plunger is fully depressed into the switch barrel.
2. Rotate the switch clockwise until travel has stopped and the switch locks fully into position. Connect the stoplight/ABS/shift lock switch electrical connector to the stoplight switch. Install sound insulator.

1. If equipped, remove the nut securing the fuel injector sight shield to the engine. Remove the oil filler neck. Lift the front of the shield up and pull towards the front of the vehicle. Remove the fuel injector sight shield from the engine.
2. Loosen the intake air duct clamps. Remove the intake duct from the air cleaner and rotate the duct upward. Remove the inlet duct by pulling upward and inboard. Remove the air cleaner assembly.
3. Remove the accelerator control cable bracket and position the cables out of the way. Remove the cruise control module and position out of the way. Disconnect the engine electrical harness at the left strut tower.
4. Disconnect the electrical connector from the EGR valve. Disconnect the engine harness clips. Position the wiring harness out of the way.
5. Disconnect the brake fluid level sensor wire connector. Remove the master cylinder attaching nuts. Remove the master cylinder from the booster and carefully position the master cylinder out of the way.
6. Remove the vacuum brake booster check valve from the booster. See «VACUUM BRAKE BOOSTER CHECK VALVE AND/OR HOSE»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) . Remove the left closeout/insulator panel. Remove the knee bolster.
7. Remove the vacuum brake booster pushrod retainer from the brake pedal clevis pin. Remove the foam spacer from the brake pedal clevis pin. Disconnect the pushrod from the brake pedal clevis pin.
8. Remove the vacuum brake booster mounting nuts from the brake pedal assembly. Remove the vacuum brake booster from the vehicle. Remove the brake booster mounting gasket, if gasket replacement is necessary.

1. Remove oil filler neck. Lift the front of the shield up and pull towards the front of the vehicle. Remove fuel injector sight shield. Remove the accelerator control cable and position the cable out of the way. Remove the accelerator control cable bracket and position the cables out of the way. Remove the cruise control module and position out of the way.
2. Disconnect the electrical connector from the EGR valve. Disconnect the engine harness clips. Position the wiring harness out of the way. Disconnect the brake fluid level sensor wire connector.
3. Remove the master cylinder attaching nuts. Remove the master cylinder from the vacuum brake booster. Carefully set the master cylinder aside. Remove the vacuum brake booster check valve from the vacuum brake booster.
4. Remove the left insulator panel. Remove the left knee bolster bracket. Remove the steering column support mounting nuts. Lower the steering column and support the steering column with mechanical wire.
5. Disconnect the stoplight/ABS/shift lock switch from the brake pedal assembly. See «STOPLIGHT SWITCH»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) . Rotate the TCC/cruise control release switch counter-clockwise to remove it from the brake pedal assembly. Disconnect the electrical connector.
6. Remove the vacuum brake booster pushrod retainer clip. Remove the vacuum brake booster foam spacer. Remove the vacuum brake booster pushrod from the brake pedal.
7. Remove the vacuum booster attaching nuts from the brake pedal assembly. Remove the vacuum brake booster from the vehicle. Remove the vacuum brake booster mounting gasket, if gasket replacement us necessary.

1. Install the brake booster mounting gasket to booster, if removed previously. Install the brake booster to the vehicle. Install the brake pedal assembly to booster stud mounting nuts and tighten them to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) .
2. Apply a small amount lubricant, (GM P/N 12346293) or equivalent to the clevis pin of the brake pedal. Connect the brake booster pushrod to the brake pedal clevis pin. Install the foam spacer to the brake pedal clevis pin. Install the booster pushrod retainer clip to the brake pedal clevis pin.
3. Install the knee bolster. Install the left closeout/insulator panel.
4. Install the master cylinder onto the vacuum brake booster. Install the master cylinder mounting nuts. See «MASTER CYLINDER»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) . Install the vacuum brake booster check valve to the booster. See «VACUUM BRAKE BOOSTER CHECK VALVE AND/OR HOSE»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) .
5. Connect the brake fluid level sensor wire connector. Install the cruise control module. Connect the electrical connector to the left strut tower.
6. Connect the electrical connector to the EGR valve. Connect the engine harness clips. Install the accelerator control cable bracket. Install the air cleaner assembly.
7. Install the intake air duct on the throttle body. Rotate the intake air duct down and install the intake air duct onto the air cleaner. Tighten the clamps to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) .
8. Align the rear edge of the fuel injector sight shield to the bracket on the rear of the engine. Push the shield down to align it with the stud and the oil filler hole. Install the oil filler neck. If equipped, install and the fuel injector sight shield nut and tighten it to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) .

1. Install the vacuum brake booster mounting gasket to booster, if removed previously. Install the booster to the vehicle.
2. Connect the vacuum brake booster pushrod to the brake pedal clevis pin. Connect the vacuum brake booster pushrod foam spacer to the brake pedal clevis pin. Install the vacuum brake booster pushrod retainer clip to the brake pedal clevis pin. Install the booster attaching nuts onto the booster studs and tighten them to specification. See «TORQUE SPECIFICATIONS»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-specifications) .
3. Connect the TCC/cruise control release switch electrical connector. Install the switch into the upper retainer. Rotate the switch clockwise until fully seated. Adjust the switch. See «TORQUE CONVERTER CLUTCH/CRUISE CONTROL RELEASE SWITCH»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__torque-converter-clutchcruise-control-release-switch) under ADJUSTMENTS & INSPECTION.
4. Connect the stoplight/ABS/shift lock switch to the brake pedal assembly. See «STOPLIGHT SWITCH»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) .
5. Install the master cylinder onto the booster. See «MASTER CYLINDER»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) .
6. Install the steering column. See appropriate STEERING COLUMNS in STEERING.
7. Install the left knee bolster bracket. Install the left insulator panel.
8. Install the vacuum booster check valve to the vacuum booster. Connect the brake fluid level sensor wire connector. Connect the cruise control module.
9. Install the accelerator control cable bracket. Install the accelerator control cable. Connect the electrical connector to the EGR valve. Connect the engine harness clips.
10. Align the extension on the rear edge of the fuel injector sight shield to the bracket on the rear of the engine. Push the shield rearward and push down to align it with the oil filler hole. Install oil filler neck.

(Scheme 6)

1. Remove the fuel injector sight shield.
2. Disconnect the vacuum hose and the brake booster vacuum check valve from vacuum brake booster.
3. Disconnect the vacuum hose from the intake manifold vacuum port.
4. Remove the brake booster vacuum check valve from the brake booster vacuum hose.

1. Install the brake booster vacuum check valve to the brake booster vacuum hose.
2. Connect the vacuum hose to the intake manifold vacuum port.
3. Connect the vacuum hose and vacuum brake booster check valve to vacuum brake booster.
4. Install the fuel injector sight shield.

Scheme 6

BRAKE CALIPER - FRONT

1. Remove the front brake caliper from the vehicle. See «BRAKE CALIPER - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-front) under REMOVAL & INSTALLATION.
2. Remove the brake caliper piston from the caliper bore by directing low pressure compressed air into the caliper bore through the fluid inlet hole.
3. Using a small wooden or plastic tool, remove the piston dust boot seal from the seal counterbore in the caliper and discard the boot seal.
4. Using a small wooden or plastic tool, remove the piston seal from the caliper bore and discard the piston seal.
5. Remove the bleeder valve and cap from the caliper.
6. Clean the brake caliper piston bore and seal counterbore, and the caliper piston with denatured alcohol, or equivalent.
7. Dry the caliper piston bore and counterbore, and the piston with non-lubricated, filtered air.
8. Inspect the caliper bore for cracks, scoring, pitting, excessive rust, and/or excessive corrosion.
9. If light rust or light corrosion are present in the caliper bore, attempt to remove the imperfection with a fine emery paper. If the imperfection cannot be removed, replace the caliper assembly.
10. If cracks, scoring, pitting, excessive rust, and/or excessive corrosion are present in the caliper bore, replace the caliper assembly.
11. Inspect the caliper piston for cracks, scoring, and/or damage to the chrome plating. Replace the caliper piston if any of these conditions exist.
12. Lubricate the new piston seal with Delco Supreme 11(R), GM P/N 12377967 (Canadian P/N 992667) or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.
13. Install the lubricated, new piston seal into the caliper bore.
14. Install the caliper piston into the caliper bore.
15. Install the NEW piston dust boot seal over the piston.
16. Using the Caliper Piston Seal Installer (J-35777) fully seat the boot in the caliper.
17. Install the bleeder valve and cap to the caliper and tighten the valve securely.
18. Install the caliper to the vehicle. See «BRAKE CALIPER - FRONT»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-front) under REMOVAL & INSTALLATION.

Disassembly

1. Remove the brake master cylinder from the vehicle. See «MASTER CYLINDER»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION.
2. Secure the mounting flange of the brake master cylinder in a bench vise so that the rear of the primary piston is accessible.
3. Clean the outside of the master cylinder reservoir on and around the reservoir cap prior to removing the cap and diaphragm.
4. Remove the reservoir cap and diaphragm from the reservoir.
5. Inspect the reservoir cap and diaphragm for the following conditions. If any of these conditions are present, replace the affected components. Cuts or cracks Nicks or deformation
6. Remove the master cylinder reservoir from the master cylinder. See «MASTER CYLINDER RESERVOIR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION.
7. Using a smooth, round-ended tool, depress the primary piston and remove the piston retainer.
8. Remove the primary piston assembly from the cylinder bore.
9. Plug the cylinder inlet ports and the rear outlet port. Apply low pressure, non-lubricated, filtered air into the front outlet port, in order the remove the secondary piston with the primary and secondary seals, and the return spring.
10. Discard the primary piston assembly, the piston retainer, and the seals and seal retainer from the secondary piston.

Assembly

Note. DO NOT use abrasives to clean the brake master cylinder bore.

1. Clean the interior and exterior of the master cylinder, the secondary piston, and the return spring in denatured alcohol, or equivalent.
2. Inspect the master cylinder bore, inlet and outlet ports, the secondary piston, and the return spring for cracks, scoring, pitting, and/or corrosion. Replace the master cylinder if any of these conditions exist.
3. Dry the master cylinder and the individual components with non-lubricated, filtered air.
4. Lubricate the master cylinder bore, the secondary piston, the return spring, and all of the individual overhaul components with Delco Supreme 11(R), GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.
5. Assemble the lubricated, new primary seal and retainer, and new secondary seal onto the secondary piston.
6. Install the lubricated return spring and secondary piston assembly into the cylinder bore.
7. Install the lubricated, NEW primary piston assembly into the cylinder bore.
8. Using a smooth, round-ended tool, depress the primary piston and install the new piston retainer.
9. Install the master cylinder reservoir to the master cylinder. See «MASTER CYLINDER RESERVOIR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION.
10. Install the reservoir cap and diaphragm to the reservoir.
11. Install the master cylinder to the vehicle. See «MASTER CYLINDER»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes) under REMOVAL & INSTALLATION.

BRAKE CALIPER - REAR

1. Remove the rear brake caliper from vehicle. See «BRAKE CALIPER - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-rear) . If the brake caliper was leaking brake fluid from the REAR of the caliper past the integral park brake actuator shaft seal, replace the brake caliper assembly. The park brake integral mechanism contains a non-serviceable seal which may be allowing brake fluid to leak past it and into the non-serviceable integral park brake mechanism.
2. Remove the caliper sleeves from the caliper mounting holes.
3. Remove the brake caliper sleeve dust boots.
4. Using a small wooden or plastic tool, carefully remove the brake caliper piston dust boot seal retaining ring from the groove in the caliper seal counterbore.
5. Using a spanner type wrench, rotate the brake caliper piston counterclockwise to remove the piston with the dust boot seal from the caliper.
6. Remove the piston dust boot seal from the piston and discard the boot seal.
7. Using a small wooden or plastic tool, remove the piston seal from the caliper bore and discard the piston seal.
8. Remove the bleeder valve from the caliper body.
9. Using a flat bladed tool, carefully reposition the park brake actuator lever return spring from the park brake actuator lever to relieve tension on the lever.
10. Inspect the operation of the integral park brake mechanism; rotate the park brake lever back and forth while observing the movement of the park brake mechanism actuator assembly in the caliper bore.
11. If the integral park brake mechanism was not operating properly binding or seized, replace the brake caliper assembly.
12. Clean the brake caliper piston bore and seal counterbore, the caliper piston, and the caliper sleeves with denatured alcohol, or equivalent.
13. Dry the caliper piston bore and counterbore, the piston, and the sleeves with non-lubricated, filtered air.
14. Inspect the caliper bore for cracks, scoring, pitting, excessive rust, and/or excessive corrosion.
15. If light rust or light corrosion are present in the caliper bore, attempt to remove the imperfection with a fine emery paper. If the imperfection cannot be removed, replace the caliper assembly.
16. If cracks, scoring, pitting, excessive rust, and/or excessive corrosion are present in the caliper bore, replace the caliper assembly.
17. Inspect the caliper piston for cracks, scoring, damage to the chrome plating, and/or damage to the integral adjusting mechanism. Replace the caliper piston if any of these conditions exist.
18. Inspect the caliper sleeves for cracks, scoring, pitting, rust, and/or corrosion. Replace the sleeves if any of these conditions exist.
19. Inspect the caliper sleeve dust boots for cracks, cuts, tears, or deterioration. Replace the boots if any of these conditions exist.
20. Inspect the caliper mounting holes for cracks, scoring, pitting, rust, and/or excessive corrosion. Replace the caliper assembly if any of these conditions exist.
21. Remove the park brake lever return spring from the park brake lever.
22. Remove the nut retaining the park brake lever to the park brake actuator shaft.
23. Remove the park brake lever from the actuator shaft.
24. Using a flat bladed tool or a punch, carefully tap the service tab of the park brake actuator shaft seal to remove the seal from out of the seal counterbore and discard the shaft seal.
25. Inspect the park brake actuator shaft sealing surface for the following conditions: Pitting Rusting Excessive corrosion Replace the caliper assembly if any of these conditions exist.
26. Inspect the park brake actuator lever for excessive wear or deformities. Replace the actuator lever if either of these conditions exist.
27. Inspect the park brake actuator lever return spring for cracks or deformities. Replace the lever return spring if either of these conditions exist.
28. Apply a light film of high temperature silicone brake lubricant to the new park brake actuator shaft seal contact surface.
29. Install the NEW park brake actuator shaft seal to the actuator shaft and seat fully to the caliper body.
30. Install the park brake lever to the park brake actuator shaft.
31. Install the park brake lever return spring to the park brake lever.
32. Using a flat bladed tool, carefully position and secure the park brake actuator lever return spring to the park brake actuator lever.
33. Lubricate the new piston seal with Delco Supreme 11(R), GM P/N 12377967 (Canadian P/N 992667) or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.
34. Install the lubricated, NEW piston seal into the caliper bore.
35. Install the NEW dust boot seal onto the caliper piston.
36. Insert the caliper piston into the caliper bore; using a spanner type wrench, rotate the piston clockwise to fully seat the piston into the caliper body.
37. Fully seat the piston dust boot seal in the seal counterbore.
38. Install the piston dust boot seal retaining ring to the groove in the caliper seal counterbore.
39. Install the caliper bleeder valve to the brake caliper and tighten securely.
40. Apply high temperature silicone brake lubricant to the brake caliper sleeves and the caliper mounting holes.
41. Install the brake caliper sleeve dust boots to the caliper.
42. Install the lubricated caliper sleeves into the caliper mounting holes.
43. Install the brake caliper to the vehicle. See «BRAKE CALIPER - REAR»(/buick/lesabre/viii-2000-2005/remont/mechanical-hydraulic/#disc-brakes__brake-caliper-rear) under REMOVAL & INSTALLATION. Inspect the brake caliper for brake fluid leaks while performing the hydraulic brake system bleeding procedure after the caliper has been installed to the vehicle. If the brake caliper leaks brake fluid from the FRONT of the caliper past the piston dust boot seal, replace the caliper piston assembly. The piston integral adjustment mechanism contains a non-serviceable seal which may be allowing brake fluid to leak past it through a bleed hole near the end of the caliper piston.

DISC BRAKE SPECIFICATIONS

FRONT DISC BRAKE SPECIFICATIONS

REAR DISC BRAKE SPECIFICATIONS

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

See also:
• BRAKE SYSTEM EXTERNAL LEAK TEST
• HYDRAULIC BRAKE SYSTEM TESTING
• BRAKE WARNING INDICATOR ALWAYS ON
• BRAKE CALIPER - FRONT
• BRAKE CALIPER - REAR
• BRAKE ROTOR THICKNESS
• BRAKE ROTOR SURFACE & WEAR
• DIAGNOSTIC STARTING POINT - HYDRAULIC BRAKES
• DIAGNOSTIC SYSTEM CHECK - HYDRAULIC BRAKES
• SYMPTOMS - PARK BRAKE
• SYMPTOMS - HYDRAULIC BRAKE
• DISC BRAKE SPECIFICATIONS
• BRAKE WARNING INDICATOR INOPERATIVE
• BRAKE PULSATION
• BRAKE SYSTEM NOISE
• BRAKE PEDAL EXCESSIVE TRAVEL
• BRAKE PEDAL EXCESSIVE EFFORT
• BRAKES DRAG
• BRAKE SYSTEM SLOW RELEASE
• BRAKE FLUID LOSS
• PARK BRAKE WILL NOT HOLD OR RELEASE
• PARK BRAKE SYSTEM DESCRIPTION
• PARK BRAKE SYSTEM TESTING
• DISC BRAKE SYSTEM TESTING
• BRAKE ASSIST SYSTEM TESTING
• BRAKE SYSTEM VACUUM SOURCE TEST
• BRAKE PAD
• DISC BRAKE MOUNTING & HARDWARE - FRONT
• BRAKE PIPE
• BRAKE ROTOR REFINISHING
• BRAKE ROTOR - FRONT
• HYDRAULIC BRAKE SYSTEM FLUSHING
• HYDRAULIC BRAKE COMPONENT OPERATION VISUAL INSPECTION
• DIAGNOSTIC STARTING POINT-PARK BRAKE
• PARK BRAKE PEDAL ASSEMBLY
• TORQUE SPECIFICATIONS
• BURNISHING PADS & ROTORS
• MASTER CYLINDER BENCH BLEEDING
• TORQUE CONVERTER CLUTCH/CRUISE CONTROL RELEASE SWITCH