GM Service Manual Online
For 1990-2009 cars only

Front Brake Caliper Overhaul Single Piston

Tools Required

J 26267 Piston Seal Installer

Disassembly Procedure

  1. Drain all the brake fluid from the caliper.
  2. 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.

    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: 141  Size: SH
  3. Pad the interior of the caliper with clean shop towels.
  4. Remove the piston from the caliper bore.

  5. Object Number: 142  Size: SH
  6. Remove the boot from the caliper bore. Do not scratch the housing bore.

  7. Object Number: 143  Size: SH
  8. Remove the piston seal from the caliper bore. Do not use a metal tool.

  9. Object Number: 145  Size: SH
  10. Remove the bleeder valve from the caliper body.
  11. Clean the bleeder valve, the caliper bore, the caliper passages and the piston with denatured alcohol. Dry the parts and blow out the brake fluid passages. Use dry and filtered compressed air.
  12. Replace the piston or the caliper if any of the following conditions exist:
  13. • Scoring on the piston surface or in the caliper bore
    • Corrosion on the piston
    • Chrome plating damage on the piston
    • Corrosion in the caliper bore. Use crocus cloth in order to polish light corrosion from the caliper bore. Replace the caliper if the corrosion cannot be removed
    • Pitting in the caliper bore

Assembly Procedure


    Object Number: 1079  Size: SH
  1. Lubricate the new piston seal, the caliper bore, and the piston with clean brake fluid.

  2. Object Number: 143  Size: SH
  3. Install the piston seal. Make sure the piston seal is not twisted in the caliper bore groove.

  4. Object Number: 147  Size: SH
  5. Install the boot on the piston.

  6. Object Number: 399639  Size: SH
  7. Install the piston in the caliper bore.

  8. Object Number: 177733  Size: SH
  9. Install the boot into the caliper housing bore using J 26267 .

  10. Object Number: 145  Size: SH

    Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  11. Install the bleeder valve in the caliper body.
  12. Tighten
    Tighten the bleeder valve to 12 N·m (110 lb in).

Front Brake Caliper Overhaul Dual Piston

Tools Required

    • J 8092 Driver Handle
    • J 43885 Boot Seal Installer

Disassembly Procedure


    Object Number: 382726  Size: SH
  1. Drain all the brake fluid from the caliper.
  2. Pad the interior of the caliper with clean shop towels.
  3. 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.

    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.

  4. Remove the pistons (2) from the caliper bores.
  5. Remove the boots (1) from the caliper bores. Do not scratch the caliper bores.
  6. Remove the piston seals (3) from the caliper bores. Do not use a metal tool.
  7. Remove the bleeder valve cap (4).
  8. Remove the bleeder valve (5) from the caliper housing (6).
  9. Clean the bleeder valve, the caliper bores, the caliper passages and the pistons with denatured alcohol. Dry the parts and blow out the brake fluid passages. Use dry and filtered compressed air.
  10. Replace the pistons or the caliper if any of the following conditions exist:
  11. • Scoring on the piston surface or in the caliper bore
    • Corrosion on the piston
    • Chrome plating damage on the piston
    • Corrosion in the caliper bore. Use crocus cloth in order to polish light corrosion from the caliper bore. Replace the caliper if the corrosion cannot be removed
    • Pitting in the caliper bore

Assembly Procedure


    Object Number: 382726  Size: SH
  1. Lubricate the new piston seals (3), the caliper bores, and the pistons (2) with clean brake fluid.
  2. Install the piston seals (3). Ensure that the piston seals are not twisted in the caliper bore grooves.
  3. Install the boot seals (1) on the pistons (2).
  4. Install the pistons in the caliper bores.
  5. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  6. Install the bleeder valve (5) in the caliper housing (6).
  7. Tighten
    Tighten the bleeder valve to 7 N·m (62 lb in).

  8. Install the bleeder valve cap (4).

  9. Object Number: 537191  Size: SH
  10. Install the boot seals into the caliper housing bores using the J 43885 .