Disc Brake System Buick LaCrosse I

Fastener Tightening Specifications

Fastener Tightening Specifications

Disc Brake Component Specifications

Disc Brake Component Specifications

Diagnostic Starting Point - Disc Brakes

Begin the disc brake system diagnosis with Diagnostic Starting Point - Hydraulic Brakes in 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.

Brake Rotor Thickness Measurement

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 four 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: Specification: Front brake rotor minimum allowable thickness after refinishing 31.08 mm (1.224 in). Rear brake rotor minimum allowable thickness after refinishing 12.9 mm (0.508 in).
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. Compare the lowest thickness measurement recorded to the following specifications: Specification: Front brake rotor discard thickness 30.7 mm (1.21 in). Rear brake rotor discard thickness 12.5 mm (0.49 in).
7. If the lowest thickness measurement of the brake rotor is at or below the discard thickness specification; the rotor requires replacement.

Brake Rotor Thickness Variation Measurement

1. If the inboard friction surface of the brake rotor is not accessible, reposition and support the caliper with the brake pads. Refer to «Brake Pads Replacement - Front (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system) and/or «Brake Pads Replacement - Rear (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-pads-replacement-rear-j65) .
2. Clean the friction surfaces of the brake rotor with denatured alcohol or an equivalent approved brake cleaner.
3. Using a micrometer calibrated in thousanths-of-a-millimeter or ten-thousanths-of-an-inch, measure and record the thickness of the brake rotor at four or more points, evenly spaced around the rotor. Ensure that the measurements are only taken within the friction surfaces and that the micrometer is positioned the same distance from the outer edge of the rotor, about 13 mm (1/2 in), for each measurement.
4. Calculate the difference between the highest and lowest thickness measurements recorded to obtain the amount of thickness variation.
5. Compare the thickness variation measurement to the following specification: Specification: Brake rotor maximum allowable thickness variation: 0.02 mm (0.001 in)
6. If the brake rotor thickness variation measurement exceeds the specification, the rotor requires refinishing or replacement.

Brake Rotor Surface and Wear Inspection

1. If the inboard friction surface of the brake rotor is not accessible, reposition and support the caliper with the brake pads. Refer to «Brake Pads Replacement - Front (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system) and/or «Brake Pads Replacement - Rear (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-pads-replacement-rear-j65) .
2. Clean the friction surfaces of the brake rotor with denatured alcohol or an equivalent approved brake cleaner.
3. Inspect the friction 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
4. If the friction surfaces of the brake rotor exhibit one or more of the Braking Surface Conditions, the rotor requires refinishing or replacement.
5. Using a micrometer calibrated in thousanths-of-a-millimeter or ten-thousanths-of-an-inch, measure and record the scoring depth of any grooves present on the rotor friction surfaces.
6. Compare the groove scoring depth recorded to the following specification: Specification: Brake rotor maximum allowable scoring: 1.50 mm (0.059 in)
7. If the brake rotor scoring depth exceeds the specification or if an excessive amount of scoring is present, the rotor requires refinishing or replacement.

Tools Required

1. J 39544-KIT Torque-Limiting Socket Set or equivalent. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .
2. J 41013 Rotor Resurfacing Kit. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .
3. J 42450-A Wheel Hub Resurfacing Kit. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .
4. J 45101 Hub and Wheel Runout Gage. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .
5. J 45101-100 Conical Brake Rotor Washers. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .

Procedure

1. Matchmark the position of the brake rotor to the wheel studs if this has not been done already.
2. Inspect the mating surface of the hub/axle flange and the brake rotor to ensure that there are no foreign particles, corrosion, rust or debris remaining. If the wheel hub/axle flange and/or if the brake rotor mating surfaces exhibit these conditions, perform the following steps: Remove the brake rotor from the vehicle. Refer to «Brake Rotor Replacement - Front (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-rotor-replacement-front-j65) and/or «Brake Rotor Replacement - Rear (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-rotor-replacement-rear-j65) . Using the J 42450-A , thoroughly clean any rust or corrosion from the mating surface of the hub/axle flange. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) . Using the J 41013 , thoroughly clean any rust or corrosion from the mating surface of the brake rotor. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) . Clean the friction surfaces of the brake rotor with denatured alcohol or an equivalent approved brake cleaner.
3. Install the rotor to the hub/axle flange using the matchmark made prior to removal.
4. Hold the rotor firmly in place against the hub/axle flange and install one of the J 45101-100 (1) and one lug nut (2) onto the upper-most wheel stud. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .
5. Continue to hold the rotor secure and tighten the lug nut firmly by hand.
6. Install the remaining J 45101-100 and lug nuts onto the wheel studs and tighten the nuts firmly by hand in a star-pattern. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .
7. Using the J 39544-KIT or equivalent, tighten the lug nuts in a star-pattern to specification, in order to properly secure the rotor. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) . Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
8. If the brake rotor has been REFINISHED or REPLACED with a new rotor, proceed to step 14.
9. If the brake rotor meets the following criteria, proceed to step 10. The rotor is within specifications and is being REUSED The rotor has NOT been refinished The rotor does NOT exhibit thickness variation exceeding the maximum allowable level
10. Mount a dial indicator, J 45101 or equivalent, to the steering knuckle and position the indicator button so it contacts the brake rotor friction surface at a 90 degree angle, approximately 13 mm (0. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .5 in) from the outer edge of the rotor.
11. Measure and record the assembled LRO of the brake rotor. Rotate the rotor until the lowest reading is displayed on the indicator dial, then set the dial to zero. Rotate the rotor until the highest reading is displayed on the dial. Mark the location of the high spot relative to the nearest wheel stud or studs. Measure and record the amount of LRO.
12. Compare the brake rotor assembled LRO to the following specification: Specification: Front brake rotor maximum allowable assembled lateral runout: 0.05 mm (0.002 in) Rear brake rotor maximum allowable assembled lateral runout: 0.05 mm (0.002 in)
13. If the brake rotor assembled LRO is within specifications, proceed to step 18. If the brake rotor assembled LRO exceeds the specification, refinish the rotor to ensure true parallelism, refer to «Brake Rotor Refinishing»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-rotor-refinishing) . After refinishing the rotor, proceed to step 14.
14. Mount a dial indicator, J 45101 or equivalent, to the steering knuckle and position the indicator button so it contacts the brake rotor friction surface at a 90 degree angle, approximately 13 mm (0. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .5 in) from the outer edge of the rotor.
15. Measure and record the assembled LRO of the brake rotor. Rotate the rotor until the lowest reading is displayed on the indicator dial, then set the dial to zero. Rotate the rotor until the highest reading is displayed on the dial. Mark the location of the high spot relative to the nearest wheel stud or studs. Measure and record the amount of LRO.
16. Compare the brake rotor assembled LRO to the following specification: Specification: Front brake rotor maximum allowable assembled lateral runout: 0.05 mm (0.002 in) Rear brake rotor maximum allowable assembled lateral runout: 0.05 mm (0.002 in)
17. If the brake rotor assembled LRO measurement exceeds the specification, bring the LRO to within specifications. Refer to «Brake Rotor Assembled Lateral Runout (LRO) Correction»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system) .
18. If the brake rotor assembled LRO measurement is within specification, install the brake caliper and depress the brake pedal several times to secure the rotor in place before removing the J 45101-100 and the lug nuts. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .

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 (3). 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 (3) 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 (1). When the disc brake pad wear reaches the minimum allowable thickness, the wear sensor contacts the disc brake rotor (2). 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 (3) is worn to within 0.76 mm (0.030 in) 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 0.13 mm (0.005 in) 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 Caliper Inspection

1. Inspect the brake caliper housing (1) 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 (2) 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 (2) 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 pistons into the caliper bores: The movement of the caliper pistons into the caliper bores should be smooth and even. If the caliper piston is frozen or difficult to bottom, the caliper requires overhaul or replacement.
5. For front caliper applications insert a discarded inner brake pad (2) or a block of wood in front of the piston. Using a large C-clamp (1) installed over the body of the caliper (3) and against the brake pad or block of wood, slowly bottom the piston on the bore.
6. For rear applications, retract the brake caliper piston (2) into the brake caliper bore utilizing a suitable spanner-type tool and fully bottoming out the piston by turning clockwise using the MAC®Tools DBC 2500 MA Disc Brake Caliper Tool Set or equivalent.

Disc Brake Mounting and Hardware Inspection - Front

1. Remove the disc brake caliper from the caliper mounting bracket.
2. Remove the disc brake pads from the caliper mounting bracket.
3. Inspect the disc brake pad mounting hardware for the following: Missing mounting hardware Excessive corrosion Bent mounting tabs Looseness at the caliper mounting bracket Looseness at the disc brake pads
4. If any of the conditions listed are found, the disc brake pad mounting hardware requires replacement.
5. Ensure the disc brake pads are held firmly in place on the caliper mounting bracket, yet slide easily on the mounting hardware without binding.
6. Inspect the caliper bolts (1) for the following: Binding Seizing Looseness in the caliper mounting bracket (3) Bent or damaged caliper bolts Cracked or torn boots (4) Missing boots Bent or damaged caliper mounting bracket (3)
7. If any of the conditions listed are found, the caliper mounting hardware requires replacement.
8. Install the disc brake pads to the caliper mounting bracket.
9. Install the disc brake caliper to the mounting bracket.

Disc Brake Mounting and Hardware Inspection - Rear

1. Grasp the brake caliper and try to move the brake caliper up or down. The brake caliper should not have excessive looseness.
2. Grasp the brake caliper and try to move the brake caliper in and out. The brake caliper should slide smoothly with minimal force.
3. Inspect the brake caliper retainers (1).
4. 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
5. If any of the conditions listed are found, the disc brake pad mounting hardware requires replacement.
6. 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.
7. 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
8. If any of the conditions listed are found, the brake caliper mounting hardware requires replacement.

Removal Procedure

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, then no brake fluid needs to be removed from the reservoir before proceeding. If the brake fluid level is higher than midway between the maximum-full point and the minimum allowable level, then remove brake fluid to the midway point before proceeding.
3. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
4. Remove the tire and the wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
5. Hand tighten 2 wheel lug nuts in order to retain the rotor to the hub.
6. Compress the front caliper piston. Install a large C-clamp (2) over the top of the caliper housing (1) and against the back of the outboard pad. Slowly tighten the C-clamp (2) until the piston pushes into the caliper bore enough to slide the caliper (1) off the rotor. Remove the C-clamp from the caliper.
7. Remove the lower caliper bolt (1).
8. In order to access the pads, rotate the caliper upward and suitably support it.
9. Remove the pads (5) from the caliper bracket (3).
10. Remove the 2 retainer slides (4) from the caliper bracket (3).
11. Inspect the following parts for cuts, tears or deterioration. Replace any damaged parts: The disc brake mounting and hardware - Refer to «Disc Brake Mounting and Hardware Inspection - Front»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__disc-brake-mounting-and-hardware-inspection) . The caliper dust boot - Refer to «Brake Caliper Inspection»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-caliper-inspection) .
12. Inspect the caliper bolts (1) for corrosion or damage. If corrosion is found, use new caliper bolts when installing the caliper.

Installation Procedure

1. Using a C-clamp, bottom the piston into the caliper bore. Use an old brake pad or wooden block across the face of the piston. Do not damage the piston or the caliper boot.
2. Install the 2 retainers to the caliper bracket.
3. Install the pads (5) to the caliper anchor bracket (3).
4. Remove the support and reposition the caliper (2) back down over the front pads.
5. Lubricate the pin bolt and the inner diameter of the bolt boot with GM P/N 18047666 or equivalent. Do not lubricate the threads of the pin bolt.
6. Install the lower caliper bolt. Tighten: Tighten the caliper bolts to 95 N.m (70 lb ft).
7. Remove the 2 wheel lug nuts retaining the rotor to the hub.
8. Install the tire and the wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
9. Lower the vehicle.
10. With the engine OFF, gradually apply the brake pedal to approximately 2/3 of its travel distance.
11. Slowly release the brake pedal.
12. Wait 15 seconds, then repeat steps 10 and 11 until a firm brake pedal is obtained. This will properly seat the brake caliper pistons and brake pads.
13. Fill the brake master cylinder reservoir to the proper level. Refer to «Master Cylinder Reservoir Filling»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#hydraulic-brake-system__master-cylinder-reservoir-filling) in Hydraulic Brakes.
14. Burnish the pads and rotors. Refer to «Burnishing Pads and Rotors»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__burnishing-pads-and-rotors) .

Brake Pads Replacement - Rear (J65, JL9)

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. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
5. Remove the tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
6. Unclamp the wheel speed sensor (WSS) harness from the lower control arm.
7. Remove both upper and lower caliper bolts (3) from the caliper (1).
8. Pull the caliper (2) straight off of the bracket and secure out of the way with heavy mechanics wire (1). DO NOT disconnect the hydraulic brake flexible hose from the caliper.
9. Remove the inboard and outboard pads from the brake caliper bracket.

1. Inspect the brake caliper bracket guide boot assembly for condition. Refer to «Disc Brake Hardware Replacement - Rear»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__disc-brake-hardware-replacement-rear) .
2. Clean the brake pad hardware mating surfaces on the caliper bracket of any debris or corrosion.
3. Inspect the brake pad retainer clips for condition and replace, if necessary.
4. Inspect the piston boot for condition. Replace if damaged. Refer to «Brake Caliper Overhaul - Rear»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system) .

1. Retract the brake caliper piston (2) into the brake caliper bore. Use a suitable spanner type wrench and turn the piston clockwise until it bottoms out fully in the brake caliper (Mac® Tools DBC 25 C 2500 MA Disc Brake Caliper Tool Set or equivalent).
2. Align the indents on the piston face to match the pin on the back of the inboard brake pads.
3. Install the brake pad retainers into the brake caliper bracket.
4. Install the inboard and outboard brake pads into the brake caliper bracket insuring that the pad with the metallic wear sensor is placed on the inboard side of the bracket.
5. Slide the caliper onto the bracket insuring that the bracket guide boots are not damaged.
6. Insert the brake caliper bolts. Tighten: Tighten the brake caliper bolts to 34 N.m (25 lb ft).
7. Re-clamp the WSS harness onto the lower control arm.
8. Install the tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
9. Lower the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
10. With the engine OFF, gradually apply the brake pedal to approximately 2/3 of its travel distance.
11. Slowly release the brake pedal.
12. Wait 15 seconds, then repeat steps 10-11 until a firm brake pedal apply is obtained. This will properly seat the brake caliper pistons and brake pads.
13. Fill the brake master cylinder reservoir to the proper level. Refer to «Master Cylinder Reservoir Filling»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#hydraulic-brake-system__master-cylinder-reservoir-filling) in Hydraulic Brakes.
14. Burnish the pads and rotors. Refer to «Burnishing Pads and Rotors»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__burnishing-pads-and-rotors) .

Burnishing Pads and 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 48 km/h (30 mph). IMPORTANT: Use care to avoid overheating the brakes while performing this step.
3. Using moderate to firm pressure, apply the brakes to bring the vehicle to a stop. Do not allow the brakes to lock.
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.

Note. Refer to Brake Fluid Effects on Paint and Electrical Components Notice in Cautions and Notices.

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, then no brake fluid needs to be removed from the reservoir before proceeding. If the brake fluid level is higher than midway between the maximum-full point and the minimum allowable level, then remove brake fluid to the midway point before proceeding.
3. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
4. Remove the front tire and the wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
5. Hand tighten 2 wheel lug nuts to retain the rotor to the hub.
6. Install a large C-clamp (2) over the top of the brake caliper and against the back of the outboard brake pad.
7. Tighten the C-clamp until the caliper piston is pushed into the caliper bore enough to slide the caliper off the rotor.
8. Remove the C-clamp from the caliper.
9. Remove the brake hose-to-caliper bolt (1) from the caliper. Discard the 2 copper brake hose gaskets (3). These gaskets may be stuck to the brake caliper and/or the brake hose end.
10. Plug the opening in the front brake hose (2) to prevent excessive brake fluid loss and contamination.
11. Remove the caliper pin bolts (1). Note the location of the caliper pin bolts. The leading caliper pin or top bolt, has a bushing as part of the assembly. The trailing caliper pin or bottom bolt, is a solid design.
12. Remove the caliper (2) from the rotor and the caliper bracket (3).
13. Inspect the caliper bolt boots in the caliper bracket for damage. Replace any damaged caliper bolt boots. Refer to «Disc Brake Hardware Replacement - Front»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__disc-brake-hardware-replacement-front) .
14. Inspect the caliper bolts (1) for corrosion or damage. If corrosion or damage is found, use new caliper pin bolts (1) when installing the caliper.

1. If reusing the brake caliper pin bolts, wipe away any debris and old lubricant with a with a clean shop cloth.
2. Apply lubricant, GM P/N 18047666 or equivalent, to the brake caliper pin bolts. Apply a thin layer to the pin bushing (2) and to the caliper pin bolt shank (3, 4). Ensure that there is not a buildup of excess lubricant at the end of the leading caliper pin (1), in front of the bushing.
3. Install the caliper (2) over the rotor and onto the caliper bracket (3).
4. Install the caliper pin bolts (1). The leading caliper pin bolt or top bolt, has a bushing as part of the assembly. The trailing caliper pin bolt or bottom bolt, is a solid design. Ensure that the bolt boots fit securely in the groove of the caliper pin bolts. If the boots are damaged, they must be replaced. Tighten: Tighten the bolts to 95 N.m (70 lb ft).
5. Assemble the brake hose bolt (1) and the NEW copper brake hose gaskets (3) to the brake hose (2).
6. Install the brake hose-to-caliper bolt to the brake caliper. Tighten: Tighten the bolt to 54 N.m (40 lb ft).
7. Remove the 2 wheel lug nuts retaining the rotor to the hub.
8. Install the front tire and the wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
9. Lower the vehicle.
10. Fill the master cylinder to the proper level with clean brake fluid. Refer to «Master Cylinder Reservoir Filling»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#hydraulic-brake-system__master-cylinder-reservoir-filling) in Hydraulic Brakes.
11. Bleed the brake system. Refer to «Hydraulic Brake System Bleeding (Manual)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#hydraulic-brake-system) or «Hydraulic Brake System Bleeding (Pressure)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#hydraulic-brake-system) in Hydraulic Brakes.
12. Inspect the hydraulic brake system for brake fluid leaks.

Brake Caliper Replacement - Rear (J65, JL9)

Note. Refer to Brake Fluid Effects on Paint and Electrical Components Notice in Cautions and Notices.

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. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
5. Remove the tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
6. Release tension from park brake system at the equalizer.
7. Disconnect the front and rear cables from one another at the connector clip (2).
8. Disconnect the park brake cable from the park brake lever on the brake caliper.
9. Remove the park brake cable from the caliper bracket.
10. Remove brake hose to caliper bolt.
11. Remove the brake hose from the brake caliper.
12. Remove and discard the 2 copper brake hose gaskets. These gaskets may be stuck to the brake caliper and/or the brake hose end.
13. Plug the opening in the brake caliper and brake hose to prevent fluid loss and/or contamination.
14. Remove the brake caliper bolts.
15. Remove the brake caliper.

1. Align the indents on the piston face to match the pin on the brake pad.
2. Inspect the bracket bolt guide assembly. Refer to «Disc Brake Hardware Replacement - Rear»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__disc-brake-hardware-replacement-rear) .
3. Inspect the brake pad hardware and replace if necessary.
4. Install the brake caliper onto the caliper bracket insuring that the guide boots are not damaged.
5. Install the brake caliper bolts. Tighten: Tighten the brake caliper bolts to 34 N.m (25 lb ft).
6. Remove the plugs in the brake hose end.
7. Assemble the brake hose bolt and the NEW copper brake hose gaskets to the brake hose.
8. Install the brake hose to caliper bolt to the brake caliper. When installing the right rear brake hose to caliper, hold hose up while tightening. Tighten: Tighten the brake hose to caliper bolt to 44 N.m (33 lb ft).
9. Install the park brake cable into the park brake bracket on the caliper.
10. Connect the park brake cable to the park brake lever on the brake caliper.
11. Bleed the brake system. Refer to «Hydraulic Brake System Bleeding (Manual)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#hydraulic-brake-system) or «Hydraulic Brake System Bleeding (Pressure)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#hydraulic-brake-system) in Hydraulic Brakes.
12. With the engine OFF, gradually apply the brake pedal to approximately 2/3 of its travel distance.
13. Slowly release the brake pedal.
14. Wait 15 seconds, then repeat steps 12-13 until a firm brake pedal is obtained. This will properly seat the brake caliper pistons and brake pads.
15. Adjust the park brake system. Refer to «Park Brake Adjustment (L26 and L32)»(/buick/lacrosse/i-2004-2009/remont/parking-brake-system/#parking-brake__park-brake-adjustment-l26-and-l32) in Park Brake.
16. Install the tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
17. Lower the vehicle.

Brake Caliper Overhaul - Front

Note. Refer to Brake Fluid Effects on Paint and Electrical Components Notice in Cautions and Notices.

J 35777 Caliper Piston Seal Installer. See Special Tools .

1. Remove the front brake caliper from the vehicle. Refer to «Brake Caliper Replacement - Front (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system) .
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 caliper dust boot seal (2) from the seal counterbore in the caliper (1) and discard the boot seal.
4. Using a small wooden or plastic tool, remove the piston seal (4) from the caliper bore and discard the piston seal.
5. Remove the bleeder valve (5) and cap (6) from the caliper (1).
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 finished surface area. Replace the caliper piston if any of these conditions exist.

1. Lubricate the new piston seal with Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667) or equivalent, DOT-3 brake fluid from a clean, sealed brake fluid container.
2. Install the lubricated, new piston seal into the caliper bore.
3. Install the caliper piston into the caliper bore. Press the piston to the bottom of the bore.
4. Install the new piston dust boot seal over the piston.
5. Use J 35777 to fully seat the caliper piston seal into the counterbore. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .
6. Install the bleeder valve and cap to the caliper and tighten the valve securely.
7. Install the front brake caliper to the vehicle. Refer to «Brake Caliper Replacement - Front (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system) .

1. Remove the rear brake caliper from vehicle. Refer to «Brake Caliper Replacement - Rear (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-caliper-replacement-rear-j65) .
2. Drain the brake fluid from the caliper assembly.
3. 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.
4. Place a block of wood against the inside of the caliper body, opposite of the caliper piston.
5. Direct low pressure compressed air through the caliper inlet hose to remove the caliper piston.
6. Remove the piston dust boot seal (2) from the seal counterbore in the caliper and discard the dust boot seal.
7. Using a small wooden or plastic tool, remove the piston seal from the caliper bore and discard the piston seal.
8. 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.
9. If the integral park brake mechanism was not operating properly (binding or seized), replace the brake caliper assembly.

1. If cracks, scoring, pitting, excessive rust, and/or excessive corrosion are present in the caliper bore, replace the caliper assembly.
2. 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.
3. Clean the brake caliper piston bore and seal counterbore, the caliper piston and the caliper sleeves with denatured alcohol or equivalent.
4. Dry the caliper piston bore and counterbore, the piston and the sleeves with non-lubricated, filtered air.
5. 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.
6. Inspect the caliper mounting holes for cracks, scoring, pitting, rust, and/or excessive corrosion. Replace the caliper assembly if any of these conditions exist.
7. Lubricate the new piston seal with Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667) or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.
8. Install the lubricated, new piston seal into the caliper bore.
9. Install the new dust boot seal onto the caliper piston (2).
10. Insert the caliper piston into the caliper bore; using a spanner type wrench, rotate the piston (2) clockwise to fully seat the piston into the caliper body (1).
11. Fully seat the piston dust boot seal in the seal counterbore.
12. Install the piston dust boot seal retaining ring to the groove in the caliper seal counterbore.
13. Install the brake caliper to the vehicle. Refer to «Brake Caliper Replacement - Rear (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-caliper-replacement-rear-j65) . 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 Hardware Replacement - Front

1. Remove the brake caliper from the mounting bracket and support the brake caliper (2) with heavy mechanic's wire (1) 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. Refer to «Brake Caliper Replacement - Front (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system) .
2. Remove the brake pads (2) from the brake caliper bracket.
3. Remove the brake pad retainers (1) from the brake caliper bracket.
4. Remove the brake caliper bracket. Refer to «Brake Caliper Bracket Replacement - Front (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-caliper-bracket-replacement-front) .
5. Mount the brake caliper bracket (1) in a vise.
6. Using a flat bladed tool or punch carefully remove the caliper pin boots (2) from brake caliper bracket (1).
7. Thoroughly clean the caliper bracket bores of all lubricant.

1. Lubricate the bores (3), the inside part of the bolt boot (2) and the caliper pin bolts (4) with GM P/N 18047666 or equivalent.
2. Press the new caliper pin bolt boots into the caliper pin bores.
3. Install the brake caliper bracket. Refer to «Brake Caliper Bracket Replacement - Front (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-caliper-bracket-replacement-front) .
4. Install the brake pad retainers (1) to the caliper bracket.
5. Install the brake pads (2) to the caliper bracket.
6. Remove the heavy mechanics wire (1) and install the brake caliper. Refer to «Brake Caliper Replacement - Front (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system) .

Disc Brake Hardware Replacement - Rear

1. Remove the brake caliper from the mounting bracket and support the brake caliper (2) with heavy mechanic's wire (1) or equivalent. It is not necessary to disconnect the hydraulic brake flexible hose from the caliper. Refer to «Brake Caliper Replacement - Rear (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-caliper-replacement-rear-j65) .
2. Remove the brake pads (9, 10) from the brake caliper bracket (12).
3. Remove the brake pad retainers (11) from the brake caliper bracket (12).
4. Remove the brake caliper bracket (12). Refer to «Brake Caliper Bracket Replacement - Rear (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-caliper-bracket-replacement-rear) .
5. Mount the brake caliper bracket (12) in a vise.

1. Clean all parts in clean, denatured alcohol.
2. Dry with low pressure, non-lubricated, filtered air.
3. Inspect the brake caliper bracket for cracks. If cracked, replace bracket.
4. Lubricate the brake caliper pin bolt sleeves with high temperature silicone lubricant.
5. Install the brake caliper bracket. Refer to «Brake Caliper Bracket Replacement - Rear (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-caliper-bracket-replacement-rear) .
6. Install the brake pad retainers (11) to the bracket caliper bracket (12).
7. Install the brake pads (9, 10) to the bracket caliper bracket (12).
8. Install the brake caliper (15) to the brake caliper bracket (12). Refer to «Brake Caliper Replacement - Rear (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-caliper-replacement-rear-j65) .

Brake Caliper Bracket Replacement - Front (J65, JL9)

1. Remove the caliper from the mounting bracket and support the caliper with heavy mechanics wire or equivalent. It is not necessary to disconnect the hydraulic brake flexible hose from the caliper. Refer to «Brake Caliper Replacement - Front (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system) .
2. Remove the front brake pads.
3. Remove the caliper bracket bolts (2).
4. Remove the caliper bracket (1).

1. Clean and visually inspect threads of the caliper bracket bolts (2) and mounting holes in the knuckle.
2. Apply THREADLOCKER, GM P/N 12345493 (Canadian P/N 10953488) or equivalent, to the threads of the brake caliper bracket bolts (2).
3. Install the caliper bracket (1) with the bracket bolts (2). Tighten: Tighten the caliper bracket bolts to 180 N.m (133 lb ft).
4. Install the front brake pads.
5. Install the caliper. Refer to «Brake Caliper Replacement - Front (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system) .

Brake Caliper Bracket Replacement - Rear (J65, JL9)

1. Remove the brake caliper from the mounting bracket and support the brake caliper (2) with heavy mechanics wire (1) or equivalent. Do NOT disconnect the hydraulic brake flexible hose from the caliper. Refer to «Brake Caliper Replacement - Rear (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-caliper-replacement-rear-j65) .
2. Remove the brake pads from the brake caliper bracket (3).
3. Remove the brake pad retainers from the brake caliper bracket (3).
4. Remove the brake caliper bracket bolts (1).
5. Remove the rear brake caliper bracket.
6. Use a wire brush to remove any rust and debris from the brake caliper bracket.
7. Inspect the brake mounting and hardware. Refer to «Disc Brake Hardware Replacement - Rear»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__disc-brake-hardware-replacement-rear) .

1. Install the brake caliper bracket.
2. Install the brake caliper bracket bolts (1). Tighten: Tighten the rear brake caliper bracket bolts to 130 N.m (96 lb ft).
3. Lubricate the brake caliper pin bolts with a thin coat of high temperature silicone lube.
4. Install the brake pad retainers to the brake caliper bracket.
5. Install the brake pads to the brake caliper bracket.
6. Install the brake caliper. Refer to «Brake Caliper Replacement - Rear (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-caliper-replacement-rear-j65) .

Brake Rotor Replacement - Front (J65, JL9)

1. J 41013 Rotor Resurfacing Kit. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .
2. J 42450-A Wheel Hub Resurfacing Kit. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
3. Install a C-clamp (2) over the body of the brake caliper, with the C-clamp ends against the rear of the caliper body and the outboard disc brake pad.
4. Using the C-clamp (2), compress the piston into the caliper bore just enough to allow the caliper (1) to slide away from the rotor.
5. Remove the C-clamp (2).
6. Remove the caliper bracket bolts. Do not disconnect the brake flexible hose bolt. Remove the brake caliper and the caliper mounting bracket as an assembly (1) from the suspension knuckle and support the assembly with heavy mechanic's wire (2) or equivalent. Ensure that there is no tension on the hydraulic brake flexible hose. Refer to «Brake Caliper Bracket Replacement - Front (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-caliper-bracket-replacement-front) .
7. Matchmark the position of the brake rotor (1) to the wheel studs.
8. Remove the brake rotor (1).

1. Using the J 42450-A , thoroughly clean any rust or corrosion from the mating surface of the hub/axle flange (2). See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .
2. Using the J 41013 , thoroughly clean any rust or corrosion from the mating surface and mounting surface of the brake rotor (1). See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .
3. Inspect the mating surfaces of the hub/axle flange and the rotor to ensure that there are no foreign particles or debris remaining.
4. Install the brake rotor to the hub/axle flange. Use the matchmark made prior to removal for proper orientation to the flange.
5. If the brake rotor was removed and installed as part of a brake system repair, measure the assembled lateral runout (LRO) of the brake rotor to ensure optimum performance of the disc brakes. Refer to «Brake Rotor Assembled Lateral Runout (LRO) Measurement»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system) .
6. If the brake rotor assembled LRO measurement exceeds the specification, bring the LRO to within specifications. Refer to «Brake Rotor Assembled Lateral Runout (LRO) Correction»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system) .
7. Install the brake caliper and the brake caliper bracket as an assembly to the suspension knuckle. Refer to «Brake Caliper Bracket Replacement - Front (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-caliper-bracket-replacement-front) .
8. Install the tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
9. Lower the vehicle.
10. If the brake rotor was refinished or replaced or if new brake pads were installed, burnish the pads and rotors. Refer to «Burnishing Pads and Rotors»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__burnishing-pads-and-rotors) .

Brake Rotor Replacement - Rear (J65, JL9)

1. J 41013 Rotor Resurfacing Kit. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .
2. J 42450-A Wheel Hub Resurfacing Kit. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/buick/lacrosse/i-2004-2009/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
3. Remove the caliper bracket bolts (1).
4. Remove the brake caliper and the caliper mounting bracket as an assembly from the suspension knuckle and support the assembly with heavy mechanic's wire or equivalent. Ensure that there is no tension on the hydraulic brake flexible hose. Refer to «Brake Caliper Bracket Replacement - Rear (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-caliper-bracket-replacement-rear) .
5. Matchmark the position of the brake rotor to the wheel studs.
6. Remove the brake rotor. If the rotor is difficult to remove, ease it off by gently rotating it as you pull outward.

1. Using the J 42450-A , thoroughly clean any rust or corrosion from the mating surface of the hub/axle flange. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .
2. Using the J 41013 , thoroughly clean any rust or corrosion from the mating surface and mounting surface of the brake rotor. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .
3. Inspect the mating surfaces of the hub/axle flange and the rotor to ensure that there are no foreign particles or debris remaining.
4. Install the brake rotor to the hub/axle flange. Use the matchmark made prior to removal for proper orientation to the flange.
5. If the brake rotor was removed and installed as part of a brake system repair, measure the assembled lateral runout (LRO) of the brake rotor to ensure optimum performance of the disc brakes. Refer to «Brake Rotor Assembled Lateral Runout (LRO) Measurement»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system) .
6. If the brake rotor assembled LRO measurement exceeds the specification, bring the LRO to within specifications. Refer to «Brake Rotor Assembled Lateral Runout (LRO) Correction»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system) .
7. Install the brake caliper and the brake caliper bracket as an assembly to the suspension knuckle. Refer to «Brake Caliper Bracket Replacement - Rear (J65, JL9)»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-caliper-bracket-replacement-rear) .
8. Install the tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
9. Lower the vehicle.
10. If the brake rotor was refinished or replaced or if new brake pads were installed, burnish the pads and rotors. Refer to «Burnishing Pads and Rotors»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__burnishing-pads-and-rotors) .

1. Remove the wheel bearing/hub (3). Refer to «Wheel Bearing/Hub Replacement - Rear»(/buick/lacrosse/i-2004-2009/remont/suspension-rear/#rear-suspension-system) in Rear Suspension
2. Remove the backing plate (2) from the knuckle (1).

1. Install the backing plate (2) to the knuckle (1).
2. Install the wheel bearing/hub (3). Refer to «Wheel Bearing/Hub Replacement - Rear»(/buick/lacrosse/i-2004-2009/remont/suspension-rear/#rear-suspension-system) in Rear Suspension

Review the following acceptable methods for bringing the brake rotor assembled LRO to within specifications. Determine which method to use for the specific vehicle being repaired.

1. The indexing method of correcting assembled LRO is most effective when the LRO specification is only exceeded by a relatively small amount: 0.025-0.127 mm (0.001-0.005 in). Indexing is used to achieve the best possible match of high spots to low spots between related components. Refer to «Brake Rotor Assembled Lateral Runout (LRO) Correction - Indexing»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-rotor-assembled-lateral-runout-lro) .
2. The correction plate method of correcting assembled LRO involves the addition of a tapered plate between the brake rotor and the hub/axle flange. The correction plate method can be used to correct LRO that exceeds the specification by up to 0.23 mm (0.009 in). Refer to «Brake Rotor Assembled Lateral Runout (LRO) Correction - Correction Plates»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-rotor-assembled-lateral-runout-lro) .
3. The on-vehicle brake lathe method is used to bring the LRO to within specifications through compensating for LRO while refinishing the brake rotor. Refer to «Brake Rotor Assembled Lateral Runout (LRO) Correction - On-Vehicle Lathe»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-rotor-assembled-lateral-runout-lro) .

If the assembled LRO cannot be corrected using these methods, then other components must be suspected as causing and/or contributing to the LRO concern.

Brake Rotor Assembled Lateral Runout (LRO) Correction - Indexing

1. J 39544-KIT Torque-Limiting Socket Set or equivalent. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .
2. J 45101-100 Conical Brake Rotor Washers. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .

1. Remove the J 45101-100 and the lug nuts that were installed during the assembled LRO measurement procedure. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .
2. Inspect the mating surface of the hub/axle flange and the brake rotor to ensure that there are no foreign particles or debris remaining.
3. Index the brake rotor in a different orientation to the hub/axle flange.
4. Hold the rotor firmly in place against the hub/axle flange and install one of the J 45101-100 (1) and one lug nut (2) onto the upper-most wheel stud. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .
5. Continue to hold the rotor secure and tighten the lug nut firmly by hand.
6. Install the remaining J 45101-100 and lug nuts onto the wheel studs and tighten the nuts firmly by hand in a star-pattern. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .
7. Using the J 39544-KIT or equivalent, tighten the lug nuts in a star-pattern to specification, in order to properly secure the rotor. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) . Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
8. Measure the assembled LRO of the brake rotor. Refer to «Brake Rotor Assembled Lateral Runout (LRO) Measurement»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system) .
9. Compare the amount of change between this measurement and the original measurement.
10. If this measurement is within specifications, proceed to step 14.
11. If this measurement still exceeds specifications, repeat steps 1-9 until the best assembled LRO measurement is obtained.
12. Matchmark the final location of the rotor to the wheel studs if the orientation is different than it was originally.
13. If the brake rotor assembled LRO measurement still exceeds the maximum allowable specification, refer to «Brake Rotor Assembled Lateral Runout (LRO) Correction»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system) .
14. If the brake rotor assembled LRO is within specification, install the brake caliper and depress the brake pedal several times to secure the rotor in place before removing the J 45101-100 and the lug nuts. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .

Brake Rotor Assembled Lateral Runout (LRO) Correction - Correction Plates

1. J 39544-KIT Torque-Limiting Socket Set or equivalent. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .
2. J 45101-100 Conical Brake Rotor Washers. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .

1. Rotate the brake rotor to position the high spot, identified and marked during the brake rotor assembled LRO measurement procedure, to face upward.
2. Remove the J 45101-100 and the lug nuts that were installed during the assembled LRO measurement procedure and/or the indexing correction procedure. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .
3. Inspect the mounting surface of the hub/axle flange and the brake rotor to ensure that there are no foreign particles or debris remaining.
4. Select the correction plate, following the manufacturer's instructions, which has a specification closest to the assembled LRO measurement. For example: If the assembled LRO measurement was 0.076 mm (0.003 in), the 0.076 mm (0.003 in) correction plate would be used. If the measurement was 0.127 mm (0.005 in), the 0.152 mm (0.006 in) correction plate would be used.
5. Determine the positioning for the correction plate (1) using the high spot mark (3) made during the brake rotor assembled LRO measurement procedure.
6. Install the correction plate (1) onto the hub/axle flange, with the V-shaped notch (2) orientated to align with the high spot mark (3), that was positioned to face upward.
7. Install the brake rotor to the hub/axle flange. Use the matchmark made prior to removal for proper orientation to the flange.
8. Hold the rotor firmly in place against the hub/axle flange and install one of the J 45101-100 (1) and one lug nut (2) onto the upper-most wheel stud. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .
9. Continue to hold the rotor secure and tighten the lug nut firmly by hand.
10. Install the remaining J 45101-100 and lug nuts onto the wheel studs and tighten the nuts firmly by hand in a star-pattern. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .
11. Using the J 39544-KIT or equivalent, tighten the lug nuts in a star-pattern to specification, in order to properly secure the rotor. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) . Refer to «Tire and Wheel Removal and Installation»(/buick/lacrosse/i-2004-2009/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
12. Measure the assembled LRO of the brake rotor. Refer to «Brake Rotor Assembled Lateral Runout (LRO) Measurement»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system) .
13. If the brake rotor assembled LRO measurement still exceeds the maximum allowable specification, refer to «Brake Rotor Assembled Lateral Runout (LRO) Correction»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system) .
14. If the brake rotor assembled LRO measurement is within specification, install the brake caliper and depress the brake pedal several times to secure the rotor in place before removing the J 45101-100 and the lug nuts. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .

Brake Rotor Assembled Lateral Runout (LRO) Correction - On-Vehicle Lathe

J 45101-100 Conical Brake Rotor Washers. See Special Tools .

1. Ensure that the caliper and caliper bracket that are already being supported, are clear from contacting any rotating components, such as the brake rotor.
2. Remove the J 45101-100 and the lug nuts that were installed during the assembled LRO measurement procedure and/or the indexing correction procedure. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .
3. Inspect the mounting surface of the hub/axle flange and the brake rotor to ensure that there are no foreign particles or debris remaining.
4. Set up the lathe, following the manufacturer's instructions.
5. Refinish the brake rotor, following the brake lathe manufacturer's instructions.
6. After each successive cut, inspect the brake rotor thickness. Refer to «Brake Rotor Thickness Measurement»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-rotor-thickness-measurement) .
7. If at any time the brake rotor exceeds the minimum allowable thickness after refinish specification, the brake rotor must be replaced. After replacing the rotor, proceed to step 10.
8. 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 approved brake cleaner
9. Remove the lathe from the vehicle.
10. Measure the assembled LRO of the brake rotor. Refer to «Brake Rotor Assembled Lateral Runout (LRO) Measurement»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system) .
11. If the brake rotor assembled LRO measurement still exceeds the maximum allowable specification, refer to «Brake Rotor Assembled Lateral Runout (LRO) Correction»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system) .
12. If the brake rotor assembled LRO is within specification, install the brake caliper and depress the brake pedal several times to secure the rotor in place before removing the J 45101-100 and the lug nuts. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .

Brake Rotor Refinishing

1. J 41013 Rotor Resurfacing Kit. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .
2. J 42450-A Wheel Hub Resurfacing Kit. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .

1. Using the J 42450-A , thoroughly clean any rust or corrosion from the mating surface of the hub/axle flange. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .
2. Using the J 41013 , thoroughly clean any rust or corrosion from the mating surface and mounting surface of the brake rotor. See «Special Tools»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__special-tools) .
3. Inspect the mating surfaces of the hub/axle flange and the rotor to ensure that there are no foreign particles or debris remaining.
4. 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.
5. Ensure that any vibration dampening attachments are securely in place.
6. With the brake lathe running, slowly bring in the cutting tools until they just contact the brake rotor friction surfaces.
7. 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 friction surface on each side, the brake rotor is properly mounted to the lathe.
8. 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.
9. Following the brake lathe manufacturer's instructions, refinish the brake rotor.
10. After each successive cut, inspect the brake rotor thickness. Refer to «Brake Rotor Thickness Measurement»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system__brake-rotor-thickness-measurement) .
11. If at any time the brake rotor exceeds the minimum allowable thickness after refinish specification, the brake rotor must be replaced.
12. 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 approved brake cleaner
13. Remove the brake rotor from the brake lathe.
14. Measure the assembled lateral runout (LRO) of the brake rotor to ensure optimum performance of the disc brakes. Refer to «Brake Rotor Assembled Lateral Runout (LRO) Measurement»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system) .
15. If the brake rotor assembled LRO measurement exceeds the specification, bring the LRO to within specifications. Refer to «Brake Rotor Assembled Lateral Runout (LRO) Correction»(/buick/lacrosse/i-2004-2009/remont/mechanical-hydraulic/#disc-brake-system) .

System Component Description

The disc brake system consists of the following components

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.

Special Tools

Special Tools Illustration Tool Number/Description J 35777 Caliper Piston Seal Installer J 39544-KIT Complete Torque Socket Set - 10 Pieces J 41013 Rotor Resurfacing Kit J 42450-A Wheel Hub Resurfacing Kit J 45101 Hub and Wheel Runout Gage J 45101-100 Conical Brake Rotor Washers J 45101-100 Conical Brake Rotor Washers J 45101-100 Conical Brake Rotor Washers J 45101-100 Conical Brake Rotor Washers J 45101 Hub and Wheel Runout Gage J 45101-100 Conical Brake Rotor Washers

Scheme 8

Scheme 9

Scheme 10

Scheme 11

Scheme 12

See also:
• Diagnostic Starting Point - Hydraulic Brakes
• Brake Dust Caution
• Tire and Wheel Removal and Installation
• Lifting and Jacking the Vehicle
• FASTENER NOTICE
• Master Cylinder Reservoir Filling
• ROAD TEST CAUTION
• Brake Fluid Irritant Caution
• Brake Fluid Effects on Paint and Electrical Components Notice
• Hydraulic Brake System Bleeding (Manual)
• Park Brake Cable to Caliper Caution
• Park Brake Adjustment (L26 and L32)
• Wheel Bearing/Hub Replacement - Rear
• Brake Pads Replacement - Front (J65, JL9)
• Brake Pads Replacement - Rear (J65, JL9)
• Special Tools
• Brake Rotor Thickness Variation Measurement
• Brake Rotor Replacement - Front (J65, JL9)
• Brake Rotor Replacement - Rear (J65, JL9)
• Brake Rotor Refinishing
• Disc Brake Mounting and Hardware Inspection - Front
• Brake Caliper Inspection
• Burnishing Pads and Rotors
• Disc Brake Hardware Replacement - Rear
• Disc Brake Hardware Replacement - Front
• Brake Caliper Replacement - Rear (J65, JL9)
• Brake Caliper Bracket Replacement - Front (J65, JL9)
• Brake Caliper Bracket Replacement - Rear (J65, JL9)
• Brake Rotor Assembled Lateral Runout (LRO) Correction - Indexing
• Brake Rotor Thickness Measurement