Disc Brake System Chevrolet Aveo I

Fastener Tightening Specifications

Fastener Tightening 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.

Symptoms - Disc Brakes

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

1. Brake Action Uneven - Pulls to One Side
2. Brakes Drag
3. Brake System Noise

Brake Action Uneven - Pulls to One Side

Brakes Drag

Brake System Noise

Inspection Procedure

1. Shift the transaxle into NEUTRAL.
2. Use paint in order to mark the relative position of the following components: Brake rotor (1) Wheel Stud (2) Hub (3)
3. Remove the brake rotor. Refer to «Brake Rotor Replacement»(/chevrolet/aveo/i-2003-2008/remont/mechanical-hydraulic/#disc-brake-system) .
4. Inspect the mating surfaces of the hub flange and the brake rotor. Ensure the mating surfaces are clean and free from burrs.
5. Clean the brake pad lining contact surfaces of the brake rotor.
6. Align the marks and install the rotor to the hub flange.
7. Install the 2 detent screws in order to retain the rotor to the hub. Tighten: Tighten the detent screws to 4 N.m (35 lb ft).
8. Use a micrometer in order to measure the thickness of the brake rotor. Measure the thickness of the rotor at 4 or more points equally spaced around the rotor. Position the micrometer the same distance from the outside edge of the rotor, in the brake pad lining contact area.
9. Compare the measurements to the following specifications: Specifications: The thickness of a new brake rotor is 24 mm (0.945 in). The discard specification for the brake rotor is 22 mm (0.866 in).
10. If the smallest measurement exceeds the discard specification, you may be able to resurface the brake rotor, depending upon the thickness variation and the surface condition.
11. If the smallest measurement is equal to or less than the discard specification, replace both brake rotors. Refer to «Brake Rotor Replacement»(/chevrolet/aveo/i-2003-2008/remont/mechanical-hydraulic/#disc-brake-system) .
12. Calculate the difference between the largest and the smallest thickness measurements in order to determine the amount of thickness variation.
13. Compare the thickness variation measurements to the following specification: Specification: The maximum thickness variation of the rotor is 0.10 mm (0.004 in).
14. If the brake rotor thickness variation measurement exceeds the specification, you may be able to resurface the brake rotor, depending upon the surface condition and the assembled lateral runout (LRO).
15. Inspect the braking surfaces of the brake rotor for the following conditions: Heavy rust and/or pitting Cracks and/or heat spots Excessive blue discoloration
16. If the braking surfaces of the brake rotor exhibit one or more of the braking surface conditions, you may be able to resurface the brake rotor, depending upon the depth of the grooves and the LRO.
17. Use a micrometer in order to measure any grooves on the rotor braking surfaces.
18. Compare the groove depth to the following specification: Specification: The maximum groove depth is 0.40 mm (0.016 in).
19. If the groove depth exceeds the specification, or if an excessive amount of scoring is present, you may be able to resurface the brake rotor, depending upon the LRO.
20. Perform the following steps in order to measure and record the assembled LRO of the rotor: Install the dial indicator to the vehicle. Position the indicator button in the brake rotor friction surface area 10 mm (0.39 in) from the outer edge of the brake rotor. Verify the indicator is at a 90 degree angle to the rotor. Rotate the rotor until the indicator displays the lowest reading. Set the dial to zero. Rotate the rotor until the indicator displays the highest reading. Mark the location of the high spot relative to the nearest wheel stud or studs. Measure and record the amount of LRO.
21. Compare the LRO to the following specification: Specification: The maximum allowable LRO is 0.06 mm (0.002 in).
22. If the measurements of the rotor are within the specifications, remove the dial indicator and complete the installation of the rotor and the pads. Refer to «Brake Rotor Replacement»(/chevrolet/aveo/i-2003-2008/remont/mechanical-hydraulic/#disc-brake-system) .
23. If the LRO measurement EXCEEDS the specification, refinish the rotor in order to attain true parallelism.
24. Verify the measurements of the rotor are within the specifications.
25. If the measurements of the rotor are within the specifications, complete the installation of the rotor and the pads. Refer to «Brake Rotor Replacement»(/chevrolet/aveo/i-2003-2008/remont/mechanical-hydraulic/#disc-brake-system) .

Brake Pad Inspection

1. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/aveo/i-2003-2008/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Remove the front wheels. Refer to «Tire and Wheel Removal and Installation»(/chevrolet/aveo/i-2003-2008/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
3. Visually check the linings for minimum thickness and wear.
4. Measure the thickness.
5. Install the brake pads in axle sets only.
6. Install the front wheels. Refer to «Tire and Wheel Removal and Installation»(/chevrolet/aveo/i-2003-2008/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
7. Lower the vehicle

Removal Procedure

1. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/aveo/i-2003-2008/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. To maintain wheel balance, mark the relative positions of the wheel and the hub, and remove the front wheel. Refer to «Tire and Wheel Removal and Installation»(/chevrolet/aveo/i-2003-2008/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
3. Remove the lower bolt of the caliper assembly retaining frame.
4. Pull the caliper piston housing up.
5. Remove the brake pads.

Installation Procedure

1. Measure the minimum lining thickness. Refer to «Brake Pad Inspection»(/chevrolet/aveo/i-2003-2008/remont/mechanical-hydraulic/#disc-brake-system__brake-pad-inspection) .
2. Install the brake pads into the caliper.
3. Push the piston inward, if necessary.
4. Pull down the caliper piston housing and secure it to the retaining frame with the lower bolt. Tighten: Tighten the retaining frame-to-caliper housing bolts to 27 N.m (20 lb ft).
5. Align the marks that were made before the wheel removal and install the front wheels. Refer to «Tire and Wheel Removal and Installation»(/chevrolet/aveo/i-2003-2008/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
6. Lower the vehicle.

1. Raise and suitably support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/chevrolet/aveo/i-2003-2008/remont/hoistjack/#general-information__lifting-and-jacking-the-vehicle) in General Information.
2. Mark the position of the front wheels relative to the wheel hubs and remove the wheels. Refer to «Tire and Wheel Removal and Installation»(/chevrolet/aveo/i-2003-2008/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
3. Remove the bolt and the washers that attach the brake hose to the caliper.
4. Disconnect the brake hose, and plug the openings in the caliper and the brake hose to prevent fluid loss and contamination.
5. Remove the caliper mounting bolts from the steering knuckle, and remove the caliper assembly.

1. Install the caliper assembly with the mounting bolts. Tighten: Tighten the caliper-to-steering knuckle mounting bolts to 95 N.m (70 lb ft).
2. Connect the brake hose. Tighten: Tighten the brake hose inlet fitting-to-caliper bolt and washers to 40 N.m (30 lb ft).
3. Install the front wheels. Refer to «Tire and Wheel Removal and Installation»(/chevrolet/aveo/i-2003-2008/remont/wheel-tire-system/#tires-and-wheels) in Tires and Wheels.
4. Lower the vehicle.
5. Fill the master cylinder to the proper level with clean brake fluid.
6. Bleed the brake system. Refer to «Hydraulic Brake System Bleeding (Manual)»(/chevrolet/aveo/i-2003-2008/remont/mechanical-hydraulic/#hydraulic-brake-system) or «Hydraulic Brake System Bleeding (Pressure)»(/chevrolet/aveo/i-2003-2008/remont/mechanical-hydraulic/#hydraulic-brake-system) in Hydraulic Brakes.
7. Recheck the fluid level.
8. Repeatedly press the brake pedal to bring the pads in contact with the rotor.

Disassembly Procedure

1. Remove the caliper assembly. Refer to «Brake Caliper Replacement»(/chevrolet/aveo/i-2003-2008/remont/mechanical-hydraulic/#disc-brake-system) .
2. Remove the caliper guide pin that connects the caliper piston housing to the retaining frame.
3. Remove the bleeder valve protector and the bleeder valve.
4. Pull out the pins and the rubber boots.
5. Remove the front pad brake set, including the pad springs, from the caliper. Refer to «Brake Pads Replacement - Front»(/chevrolet/aveo/i-2003-2008/remont/mechanical-hydraulic/#disc-brake-system) .
6. Using compressed air, blow out the piston from the housing.
7. Remove the outer seal.
8. Remove the inner seal from the caliper piston bore.

Assembly Procedure

1. Clean all parts in denatured alcohol or brake fluid. Dry the parts with unlubricated compressed air and blow out all passages in the housing and the bleeder valve.
2. Inspect the piston and the caliper for scoring, nicks, and corrosion. Replace components if these elements are found.
3. Inspect the caliper bleeder valve.
4. Lubricate a new piston inner seal.
5. Install the piston inner seal into the caliper housing groove. Make sure the seal is not twisted.
6. Install the outer piston dust seal in the groove.
7. Lubricate the piston with brake fluid.
8. Push the piston into its bore and make sure the dust seal is seated in the piston groove.
9. Coat the pins with rubber grease and install the boots.
10. Install the caliper bleeder valve and the dust cap. Tighten: Tighten the caliper bleeder valve to 6 N.m (53 lb in).
11. Connect the brake pads and the pad springs.
12. Connect the retaining frame to the caliper housing with the guide pin bolts. Tighten: Tighten the retaining frame-to-caliper housing bolts to 27 N.m (20 lb ft).
13. Install the caliper assembly. Refer to «Brake Caliper Replacement»(/chevrolet/aveo/i-2003-2008/remont/mechanical-hydraulic/#disc-brake-system) .

1. Remove the caliper assembly without disconnecting the brake hoses. Refer to «Brake Caliper Replacement»(/chevrolet/aveo/i-2003-2008/remont/mechanical-hydraulic/#disc-brake-system) .
2. Remove the caliper bracket.
3. Remove the rotor-to-front wheel hub detent screw from the rotor and the front wheel hub.
4. Pull off the rotor.

1. Inspect the rotor. Refer to «Brake Rotor Surface and Wear Inspection»(/chevrolet/aveo/i-2003-2008/remont/mechanical-hydraulic/#disc-brake-system) .
2. Install the rotor to the front wheel hub by tightening the detent screw. Tighten: Tighten the rotor-to-front wheel hub detent screw to 4 N.m (35 lb in).
3. Install the caliper bracket. Tighten: Tighten the caliper bracket mounting bolts to 95 N.m (70 lb ft).
4. Install the caliper assembly. Refer to «Brake Caliper Replacement»(/chevrolet/aveo/i-2003-2008/remont/mechanical-hydraulic/#disc-brake-system) .

1. Remove the rotor. Refer to «Brake Rotor Replacement»(/chevrolet/aveo/i-2003-2008/remont/mechanical-hydraulic/#disc-brake-system) .
2. Remove the screws for the splash shield from the steering knuckle.
3. Remove the splash shield.

1. Install the splash shield.
2. Secure the splash shield to the steering knuckle with the screws. Tighten: Tighten the splash shield-to-steering knuckle screws to 4 N.m (35 lb in).
3. Install the rotor. Refer to «Brake Rotor Replacement»(/chevrolet/aveo/i-2003-2008/remont/mechanical-hydraulic/#disc-brake-system) .

Scheme 8

Note. Refer to Brake Caliper Notice in Cautions and Notices.

This caliper has a single bore and is mounted to the steering knuckle with two mounting bolts. Hydraulic pressure, created by applying the brake pedal, is converted by the caliper to a stopping force. This force acts equally against the piston (1) and the bottom of the caliper bore to move the piston outward and to slide the caliper inward, resulting in a clamping action on the rotor (2). This clamping action forces the linings against the rotor, creating friction to stop the vehicle.

1. Replace all components included in the repair kits used to service this caliper.
2. Lubricate the rubber parts with clean brake fluid to ease assembly.
3. Do not use lubricated shop air on brake parts, as damage to the rubber components may result.
4. If any hydraulic component is removed or disconnected, it may be necessary to bleed all or part of the brake system.
5. Replace the pads (3) in axle sets only.
6. The torque values specified are for dry, unlubricated fasteners.
7. Perform the service operations on a clean bench, free from all mineral oil materials.

Scheme 9

When the hydraulic pressure is applied to the piston (3), the piston moves leftward. The piston seal (2) exerts pressure against the piston and moves with the cylinder.

However, a part of the piston seal is fixed into a groove within the cylinder. The shape of the seal is distorted toward the direction the piston is moving, as shown in the figure.

When the pressure is taken off the brake pedal and the hydraulic pressure is released from the piston, a restoring elastic force is generated at the seal. This force pushes the piston rightward and back to the original position.

As the pads (1) wear away and the clearance between the rotor and the pads becomes larger, the piston moves farther.

The shape of the seal could then become more distorted. The distortion is limited to the same amount as previously described, because the end of the seal is fixed into the groove in the cylinder. The piston moves farther to cover the distance of clearance. As the piston returns by the same distance, the rubber seal recovers its original shape, and the clearance between the rotor and pads is maintained in original condition.

See also:
• Diagnostic Starting Point - Hydraulic Brakes
• Fastener Notice
• Lifting and Jacking the Vehicle
• Tire and Wheel Removal and Installation
• Brake Caliper Notice
• Brake Dust Caution
• Brake Fluid Caution
• Hydraulic Brake System Bleeding (Manual)
• Safety Glasses Caution
• Brake Rotor Replacement
• Brake Pad Inspection