Rear Brake Caliper Overhaul JL9-J55

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

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

1. Remove the rear brake caliper from the vehicle. Refer to Rear Brake Caliper Replacement.

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 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.

2. Remove the brake caliper piston from the caliper bore by directing low pressure compressed air into the caliper bore through the fluid inlet hole.



3. Using a small wooden or plastic tool, remove the piston dust boot seal (2) from the seal counterbore in the caliper (1) and discard the boot seal.
4. Using a small wooden or plastic tool, remove the piston seal (4) from the caliper bore and discard the piston seal.
5. Remove the bleeder valve (5) and cap (6) from the caliper (1).

Important: Do not use abrasives to clean the brake caliper piston.

6. Clean the brake caliper piston bore and seal counterbore, and the caliper piston with denatured alcohol, or equivalent.
7. Dry the caliper piston bore and counterbore, and the piston with non-lubricated, filtered compressed air.
8. Inspect the caliper bore for cracks, scoring, pitting, excessive rust, and/or excessive corrosion.
9. If light rust or light corrosion are present in the caliper bore, attempt to remove the imperfection with a fine emery paper. If the imperfection cannot be removed, replace the caliper assembly.
10. If cracks, scoring, pitting, excessive rust, and/or excessive corrosion are present in the caliper bore, replace the caliper assembly.
11. Inspect the caliper piston for cracks, scoring, and/or damage to the chrome plating. Replace the caliper piston if any of these conditions exist.
12. Lubricate the new piston seal with GM approved brake fluid from a clean, sealed brake fluid container. Refer to Fluid and Lubricant Recommendations.
13. Install the lubricated, new piston seal into the caliper bore.



14. Install the new piston dust boot seal over the piston.
15. Install the caliper piston into the caliper bore.

15.1.

Install the boot over the end of the piston so that the fold will face toward the brake caliper housing piston bore opening.

15.2.

Seat the boot into the brake caliper bore groove and slide the piston into the brake caliper bore.

15.3.

Push the piston down to the bottom of the brake caliper bore.

15.4.

Make sure the boot are properly seated into the piston groove and into the groove in the brake caliper bore.

Notice: Refer to Fastener Notice in the Preface section.

16. Install the caliper bleed screw.

Tighten
Tighten the screw to 12 N·m (106 lb in).

17. Install the caliper bleed screw cap.
18. Install the caliper to the vehicle. Refer to Rear Brake Caliper Replacement.