Front Brake Caliper Overhaul (J56)
Front Brake Caliper Overhaul (J56)
Warning: Refer to Brake Fluid Irritant Warning Brake Fluid Irritant Warning.
Caution: Refer to Brake Fluid Effects on Paint and Electrical Components Caution Brake Fluid Effects on Paint and Electrical Components Caution.
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.
Note:
* Replace all the components included in the repair kits used to service this brake caliper.
* Lubricate the rubber parts with GM approved brake fluid from a clean, sealed brake fluid container.
* 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 2 blocks: 19 mm (3/4 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 (3/4 in) X 51 mm (2 in) X 184 mm (7 in)
1. Remove the brake caliper from the vehicle. Refer to Front Brake Caliper Replacement (JE5, J55 (AWD)) Front Brake Caliper Replacement (JE5, J55 (AWD))Front Brake Caliper Replacement (JE5, J55 (RWD)) Front Brake Caliper Replacement (JE5, J55 (RWD))Front Brake Caliper Replacement (J56) Front Brake Caliper Replacement (J56).
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. Remove the brake caliper bleeder valve caps (1).
5. Remove the brake caliper bleeder valves (1).
6. Place an old brake pad (1) or the fabricated 184 mm (7 in) long block of wood over 3 adjoining piston bores and secure in place with a non-marring C-clamp.
7. Place the 2 fabricated 51 mm (2 in) long blocks of wood (1) over 2 of the adjoining piston bores and secure in place with a non-marring C-clamp.
8. Use clean cloths to cushion the interior of caliper housing during removal of the piston.
9. Carefully remove the brake caliper piston (1) by directing low pressure compressed air into the brake bleeder valve hole (2).
10. Move one of the fabricated 51 mm (2 in) long block of woods over the emptied piston bore and secure it in place with a non-marring C-clamp.
11. Carefully remove the brake caliper piston by directing low pressure compressed air into the brake bleeder valve hole.
12. Repeat steps 10 and 11 for the remaining brake caliper piston.
13. Repeat steps 6 through 11 for the opposite side of the caliper.
Note: Do not scratch the brake caliper piston bores.
14. Using a non-marring, flat-bladed tool, remove and discard the brake caliper dust boot seals (1).
Note: Do not scratch the brake caliper piston bores.
15. Using a non-marring, flat-bladed tool, remove and discard the brake caliper piston seals (1).
16. Remove the caliper from the vise and clean the entire caliper with denatured alcohol, or equivalent.
17. Dry the caliper piston bores with non-lubricated filtered air.
18. Inspect the caliper cylinder bores and piston seal counter-bores for scratches, cracks, pitting, and/or corrosion.
Note: Do not clean the caliper piston bores by honing or cleaning with abrasives.
19. 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
1. Install the new piston dust boot seals over the pistons. Make sure the dust boot seal is properly seated on the piston, in the dust boot seal groove.
2. Lubricate the new brake caliper piston seals (1) with GM approved or equivalent brake fluid from a clean, sealed brake fluid container.
3. Install the new piston seals into the brake caliper piston bore grooves. Make sure the seals are not twisted.
4. Apply a thin coat of GM approved or equivalent 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 184 mm (7 in) long block of wood over 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.
Caution: Refer to Fastener Caution Fastener Caution.
8. Install the brake caliper bleeder valves (1) and tighten to 14 Nm (124 lb in).
9. Install the brake caliper bleeder valve caps (1).
10. Install the caliper to the vehicle. Refer to Front Brake Caliper Replacement (JE5, J55 (AWD)) Front Brake Caliper Replacement (JE5, J55 (AWD))Front Brake Caliper Replacement (JE5, J55 (RWD)) Front Brake Caliper Replacement (JE5, J55 (RWD))Front Brake Caliper Replacement (J56) Front Brake Caliper Replacement (J56).