Front 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 front brake caliper from the vehicle. Refer to Front 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 pistons 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 seals from the seal counterbores in the caliper and discard the boot seals.
4. Using a small wooden or plastic tool, remove the piston seals from the caliper bores and discard the piston seals.
5. Remove the bleeder valve and cap from the caliper.

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

6. Clean the brake caliper piston bores and seal counterbores, and the caliper pistons with denatured alcohol, or equivalent.
7. Dry the caliper piston bores and counterbores, and the pistons with non-lubricated, filtered compressed air.
8. Inspect the caliper bores for cracks, scoring, pitting, excessive rust, and/or excessive corrosion.
9. If light rust or light corrosion are 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.
10. If cracks, scoring, pitting, excessive rust, and/or excessive corrosion are present in the caliper bores, replace the caliper assembly.
11. Inspect the caliper pistons for cracks, scoring, and/or damage to the chrome plating. Replace the caliper pistons if any of these conditions exist.
12. Lubricate the new piston seals with GM approved brake fluid from a clean, sealed brake fluid container. Refer to Fluid and Lubricant Recommendations.
13. Install the lubricated, new piston seals into the caliper bores.
14. Install the new piston dust boot seal over the piston.
15. Install the caliper pistons into the caliper bores.

15.1.

Install the boots over the ends of the pistons so that the fold will face toward the brake caliper housing piston bore openings.

15.2.

Seat the boots into the brake caliper bore grooves and slide the pistons into the brake caliper bores.

15.3.

Push the pistons down to the bottom of the brake caliper bores.

15.4.

Make sure the boots are properly seated into the piston grooves and into the groove in the brake caliper bores.

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 Front Brake Caliper Replacement.