GM Service Manual Online
For 1990-2009 cars only

Front Brake Caliper Overhaul JE5, JL9

Warning: Refer to Brake Dust Warning in the Preface section.

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

Caution: Refer to Brake Fluid Effects on Paint and Electrical Components Caution in the Preface section.

Disassembly Procedure

Note: 

   • Replace all the components included in the repair kits used to service this brake caliper.
   • Lubricate the rubber parts with new Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667) or equivalent DOT-3 brake fluid to make assembly easier.
   • If any hydraulic component is removed or disconnected, it may be necessary to bleed all or part of the brake system.
   • The torque values specified are for dry, non-lubricated fasteners.
   • Perform the service operations on a clean bench, free from all mineral oil materials.

  1. Remove the brake caliper from the vehicle. Refer to Front Brake Caliper Replacement.
  2. Drain the brake fluid from the brake caliper.

  3. Object Number: 794254  Size: SH
  4. Place a 25 mm (1 in) block of wood between the caliper and the piston.
  5. Install a large C-clamp over the body of the brake caliper with the C-clamp ends against the rear of the caliper body and against the block of wood.
  6. Carefully remove the brake caliper piston by directing low pressure compressed air into the brake caliper inlet hole.
  7. Remove the C-clamp from the caliper.
  8. Remove the block of wood from the caliper.
  9. Install clean cloths to pad the interior of the caliper housing between the remaining caliper piston and the caliper body.
  10. To cover the open caliper bore place a 25 mm (1 in) block of wood between the caliper body and the brake caliper dust boot seal.
  11. Install a large C-clamp over the body of the brake caliper with the C-clamp ends against the rear of the caliper body and against the block of wood.
  12. Carefully remove the brake caliper piston by directing low pressure compressed air into the brake caliper inlet hole.
  13. Remove the C-clamp form the caliper.
  14. Remove the block of wood from the caliper.

  15. Object Number: 806399  Size: SH
  16. Remove the piston dust boot seals (2)  from the seal counter-bores in the brake caliper and discard the boot seals.
  17. Using a small wooden or plastic tool, remove the piston seals (1) from the brake caliper bores and discard the piston seals.

  18. Object Number: 1201165  Size: SH
  19. Remove the brake caliper bleeder valve cap.
  20. Remove the brake caliper bleeder valve (1).
  21. Remove the brake caliper bleeder valve seal (2) and discard.

  22. Object Number: 171985  Size: SH

    Note: Do not use abrasives to clean the brake caliper pistons.

  23. Inspect the brake caliper mounting bracket guide surfaces for corrosion and wear. Remove and replace the brake caliper mounting bracket if damaged or worn.
  24. Clean the brake caliper piston bores and seal counter-bores with denatured alcohol, or equivalent.
  25. Clean the brake caliper pistons with denatured alcohol, or equivalent.
  26. Dry the caliper piston bores and counter-bores with non-lubricated, filtered air.
  27. Dry the brake caliper pistons with non-lubricated, filtered air.
  28. Inspect the caliper bores for cracks, scoring, pitting, excessive corrosion.
  29. If light corrosion is present in the caliper bores, attempt to remove the imperfection with a fine emery paper. If the imperfection cannot be removed, replace the caliper assembly.
  30. If cracks, scoring, pitting, and excessive corrosion are present in the caliper bores, replace the caliper assembly.
  31. Inspect the caliper pistons for cracks, scoring, and/or damage. Replace the caliper pistons if any of these conditions exist.

Assembly Procedure


    Object Number: 1201165  Size: SH
  1. Install the valve stem seal (2) over the threaded end of the bleeder valve (1).
  2. Caution: Refer to Fastener Caution in the Preface section.

  3. Install the brake caliper bleeder valve (1) and tighten to  14 N·m (124 lb in).
  4. Install the brake caliper bleeder valve cap.

  5. Object Number: 806399  Size: SH
  6. Lubricate the new piston seals (1) 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.
  7. Install lubricated piston seals into the brake caliper bore seal grooves.
  8. Make sure the seals are not twisted.

  9. Object Number: 1200888  Size: SH
  10. Install the piston dust boot (2) over the end of the piston (3) so that the fold will face toward the brake caliper housing piston bore opening.
  11. Seat the caliper dust boot into the brake caliper bore groove (1) and slide the piston into the brake caliper bore.

  12. Object Number: 1200891  Size: SH
  13. Using your fingers, carefully push the piston to the bottom of the brake caliper bore.
  14. Ensure the caliper dust boot is properly seated into the piston groove and into the groove in the brake caliper bore.
  15. Repeat steps 5 - 10 for the remaining piston.
  16. Install the brake caliper to the vehicle. Refer to Front Brake Caliper Replacement.

Front Brake Caliper Overhaul J56

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

Caution: Refer to Brake Fluid Effects on Paint and Electrical Components Caution in the Preface section.

Caution: This brake caliper is coated with a specialized paint. Use care when handling and servicing to ensure the paint does not get chipped or scratched. Clean any brake fluid from painted surfaces with denatured alcohol, or equivalent, as soon as possible.

Caution: Do not remove the caliper external crossover tube or separate the 2 caliper halves. If the crossover tube and/or the caliper halves are separated, corrosion and damage to the caliper may result.

Note: 

   • Replace all the components included in the repair kits used to service this brake caliper.
   • Lubricate the rubber parts with new Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667) or equivalent DOT-3 brake fluid to make assembly easier.
   • If any hydraulic component is removed or disconnected, it may be necessary to bleed all or part of the brake system.
   • The torque values specified are for dry, non-lubricated fasteners.
   • Perform the service operations on a clean bench, free from all mineral oil materials.

Disassembly Procedure

Warning: Do not place fingers in front of the caliper piston(s) in an attempt to catch or protect it when applying compressed air. The piston(s) can fly out with force and could result in serious bodily injury.

Caution: Use clean cloths to pad interior of caliper housing during piston removal. Use just enough air to ease the pistons out of the bores. If the pistons are blown out, even with the padding provided, it may be damaged.

Note: It will be necessary to fabricate one or more blocks of wood to the following dimensions to be used during this procedure:

   • Must fabricate 1 block: 19 mm (¾ in) X 51 mm (2 in) X 51 mm (2 in)
   • Optional to fabricate 1 block, rather than using an old brake pad: 19 mm (¾ in) X 51 mm (2 in) X 127 mm (5 in)
   • Optional to fabricate 1 block to cushion piston removal: 19 mm (¾ in) X 51 mm (2 in) X 127 mm (5 in)

  1. Remove the brake caliper from the vehicle. Refer to Front Brake Caliper Replacement.
  2. Drain the brake fluid from the brake caliper.
  3. Place the caliper in a vise using plastic vise caps or suitable material to protect the caliper mounting bosses from the vise jaws.

  4. Object Number: 1381156  Size: SH
  5. Place an old brake pad or the fabricated 127 mm (5 in) long block of wood over 2 adjoining piston bores and secure in place with a non-marring C-clamp.
  6. Place the fabricated 51 mm (2 in) long block of wood over one of the opposing piston bores and secure it in place with a non-marring C-clamp.
  7. Use clean cloths or the other fabricated 127 mm (5 in) long block of wood to pad the interior of caliper housing during removal of the piston.
  8. Carefully remove the brake caliper piston by directing low pressure compressed air into the brake caliper inlet hole. If the dust boot seal slides out with the piston, remove the dust boot seal from piston and reinstall the seal into the caliper.
  9. Move the fabricated 51 mm (2 in) long block of wood over the emptied piston bore and secure it in place with a non-marring C-clamp.
  10. Move the clean cloths or the other fabricated 127 mm (5 in) long block of wood to pad the interior of caliper housing during the removal of the piston.
  11. Carefully remove the brake caliper piston by directing low pressure compressed air into the brake caliper inlet hole. If the dust boot seal slides out with the piston, remove the dust boot seal from piston and reinstall the seal into the caliper.
  12. Repeat steps 4 through 10 for the opposite side of the caliper.

  13. Object Number: 1381161  Size: SH
  14. Using care to not scratch or mar the painted surfaces or piston bore, remove all the dust boot seals using a flat-bladed tool. Discard the dust boot seals.

  15. Object Number: 1381159  Size: SH
  16. Using wooden or plastic tool, remove the piston seals (5) from the piston bores. Discard the piston seals.
  17. Remove both brake caliper bleeder caps and valves (1, 2).
  18. Remove the caliper from the vise and clean the entire caliper with denatured alcohol, or equivalent.
  19. Dry the caliper piston bores with non-lubricated filtered air. Make sure the external crossover pipe and the internal fluid ports are clean and free of obstructions.
  20. Inspect the caliper cylinder bores and piston seal counter-bores for scratches, cracks, pitting, and/or corrosion.
  21. Note: Do NOT clean the caliper piston bores by honing or cleaning with abrasives.

  22. If the caliper piston bores are scratched, cracked, or pitted, or if corrosion cannot be cleaned with denatured alcohol, replace the caliper assembly.

Assembly Procedure


    Object Number: 1381159  Size: SH
  1. Install the new piston dust boot seals (3) over the pistons (4). Make sure the dust boot seal is properly seated on the piston, in the dust boot seal groove.
  2. Lubricate the new piston seals (5) 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.
  3. Install the lubricated, new piston seals (5) into the brake caliper bore seal grooves. Make sure the seals are not twisted.
  4. Apply a thin coat of Delco Supreme 11®, GM P/N 12377967 (Canadian P/N 992667) or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container, onto the caliper piston bores and the outer surface of the caliper pistons.
  5. Install the piston and dust boot assemblies into the correct caliper bores. Press the pistons and dust boot seals all the way in by hand.
  6. Place a clean old brake pad or the fabricated 127 mm (5 in) long block of wood over 2 adjoining piston bores and apply light pressure with non-marring C-clamp. This will ensure the dust boots and pistons are fully seated into the caliper.
  7. Repeat step 6 for the opposite pistons.
  8. Caution: Refer to Fastener Caution in the Preface section.

  9. Install the brake caliper bleeder valves (2).
  10. Tighten
    Tighten the valves to 14 N·m (124 lb in).

  11. Install the brake caliper bleeder valve caps (1).
  12. Install the caliper to the vehicle. Refer to Front Brake Caliper Replacement.