GM Service Manual Online
For 1990-2009 cars only

Disassembly Procedure

  1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  2. Remove the tire and wheel assembly. Refer to Tire and Wheel Removal and Installation in Tires and Wheels.
  3. Remove the caliper from the vehicle. Refer to Brake Caliper Replacement .
  4. Caution: Do not place your fingers in front of the piston in order to catch or protect the piston while applying compressed air. This could result in serious injury.

    Caution: Wear safety glasses in order to avoid eye damage.

    Notice: Use just enough air pressure to ease the piston out of the bore. You can damage a blown-out piston even with the padding.


    Object Number: 172792  Size: SH
  5. Insert a block of hard wood or a shop cloth (2) into the caliper interior  (1) to catch the piston as it is forced out of the bore with compressed air.
  6. Remove the piston from the caliper by applying compressed air to the caliper brake hose connector hole.
  7. Remove the rubber boot from the caliper groove.

  8. Object Number: 172800  Size: SH
  9. Use a flat plastic tool in order to remove the piston seal (1) from the caliper (2).
  10. Remove the bleeder valve from the caliper.
  11. Caution: Brake fluid may irritate eyes and skin. In case of contact, take the following actions:

       • Eye contact--rinse thoroughly with water.
       • Skin contact--wash with soap and water.
       • If ingested--consult a physician immediately.

    Notice: Brake fluid will damage electrical connections and painted surfaces. Use shop cloths, suitable containers, and fender covers to prevent brake fluid from contacting these areas. Always re-seal and wipe off brake fluid containers to prevent spills.

  12. Clean the following items in brake fluid:
  13. • The caliper set ring
    • The piston
    • The caliper cylinder bore
  14. Inspect the piston for scoring, corrosion and any damage to the chrome plating. Replace the piston if any of these conditions exist.
  15. Inspect the caliper cylinder bore for scoring, pitting and corrosion. Use a crocus cloth to polish out any light corrosion. If the corrosion cannot be removed, replace the caliper.

Assembly Procedure

  1. Install a new piston seal into the caliper bore.

  2. Object Number: 172806  Size: SH
  3. Install a new piston boot (2) onto the piston (1).

  4. Object Number: 470322  Size: SH
  5. Install the piston into the caliper (1).

  6. Object Number: 172811  Size: SH
  7. Fit the piston boot (3) onto the caliper groove.
  8. Important: Do not pull the piston out of the cylinder.

  9. Pull on the piston in order to confirm that the boot is properly fitted in the caliper groove.
  10. Push the piston into the caliper. Seat the piston in the caliper bore.
  11. Important: Tighten the bleeder valve while bleeding the hydraulic brake system.

  12. Install the bleeder valve. DO NOT tighten.
  13. Install the caliper on the vehicle. Refer to Brake Caliper Replacement .
  14. Install the tire and wheel assembly. Refer to Tire and Wheel Removal and Installation in Tires and Wheels.
  15. Lower the vehicle.
  16. Bleed the brake system. Refer to Hydraulic Brake System Bleeding in Hydraulic Brakes.