GM Service Manual Online
For 1990-2009 cars only

Tools Required

KM-286 Installing Shackle

Disassembly Procedure

    Caution: Refer to Brake Fluid Irritant Caution in the Preface section.


    Object Number: 891857  Size: SH

    Important: The rear caliper has a dual piston design. The caliper must not be completely disassembled. Only disassemble and assemble one piston at a time.

  1. Using a small screw driver, carefully pry the piston boot clamp ring from the boot.
  2. Remove the piston boot.

  3. Object Number: 891849  Size: SH

    Caution: To prevent bodily injury, make sure to keep fingers or other body parts away from piston during removal.

    Notice: Pad interior of caliper body to provide a protective cushion for piston when it exits the caliper. This will protect piston from surface damage caused from piston/caliper body contact.

  4. Block the opposite piston with the holding tool KM-286 and carefully remove the piston from the caliper by applying low pressure, non-lubricated, compressed air into the caliper inlet hole.

  5. Object Number: 891858  Size: SH
  6. Remove the piston seal from the groove of the caliper.
  7. Remove the bleeder valve and the bleeder valve cap from the caliper assembly.
  8. Clean all the parts in clean denatured alcohol. Dry with non-lubricated, low pressure, compressed air. Make sure to blow out all passages in the caliper body and the bleeder valve.
  9. Inspect the piston for scoring, nicks, cracks, wear, or corrosion. Replace the piston if any damage is found.
  10. Important: Do not hone the caliper bore.

  11. Inspect the caliper body piston bore for scoring, nicks, wear, or corrosion. Crocus cloth can be used to remove light corrosion. If more extensive damage is present, replace the caliper.
  12. Inspect the seal groove in the caliper for nicks or burrs. If present, replace the caliper.

Assembly Procedure

    Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 891858  Size: SH
  1. Install the bleeder valve and the cap into the caliper assembly.
  2. Tighten
    Tighten the rear caliper bleeder valve to 6 N·m (53 lb in).

    Important: Ensure the seal is not twisted in the groove.

  3. Lubricate the new piston seal with clean brake fluid and install into the caliper seal groove.

  4. Object Number: 891862  Size: SH
  5. Insert the piston boot into the caliper groove.
  6. Important: Ensure that the piston boot is smoothly seated in the counter bore of the caliper body.

    Important: The piston face has a notched surface cap. Position the relief notch toward the bottom side of the caliper.

  7. Insert the piston into the caliper bore.
  8. Repeat disassembly steps 1-4 and assembly steps 1-4 for the opposite caliper piston.