Front Brake Caliper Overhaul J56, J57

Special Tools

CH-47954 Caliper Seal Installer

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

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

1. Remove the front brake caliper. Refer to Front Brake Caliper Replacement.

Note: Use a vise or holding fixture that has soft jaws to prevent damage to the aluminum body of the brake caliper.

2. Install the caliper in a vise.



3. Position a tool between the inner and outer brake pads to prevent the remaining brake caliper pistons from being forced from the caliper bores.
4. Using the C-Clamp from the CH-47954 Caliper Seal Installer , hold the brake pad opposite the piston to be removed from the caliper.
5. Apply filtered, non lubricated compressed air to the brake hose fitting inlet port.



6. Remove the piston (1)  from the caliper.
7. After opposing inboard and outboard pistons have been removed, repeat Steps 3-6 for the remaining brake caliper pistons.
8. Using a plastic tool, carefully remove the dust seal (2)  from the caliper body.
9. Using a plastic tool, carefully remove the piston seal (3).




Note: Do not remove the brake caliper brake fluid transfer pipe unless the brake pipe is damaged and requires replacement.

10. Remove the brake caliper brake fluid transfer pipe, if necessary.

Caution: Refer to Fastener Caution in the Preface section.





Note: Hand install the brake pipe fittings completely before tightening.

1. Install the brake caliper brake fluid transfer pipe, if removed and tighten the brake pipe fittings to  40 N·m (30 lb ft).



2. Install the piston (1), the dust seal (2), and the piston seal (3) in the brake caliper piston bore.




Note: When the brake caliper piston dust seal is properly installed, the seal may protrude slightly above the surface of the brake caliper. This is a normal condition due to the slight curvature of the brake caliper.

3. Using the CH-47954 Caliper Seal Installer , install the dust seal:

3.1.	Position the C-Clamp and cup on the caliper.

3.2.	Align the tool on the dust seal to ensure correct installation of the dust seal.

3.3.	Using the C-clamp, slowly apply pressure to the dust seal.

3.4.	Check the alignment of the dust seal to the brake caliper bore.

3.5.	If the position of the tool and dust seal has changed, reposition the tool on seal.

3.6.	Fully seat the dust seal in the piston bore.

3.7.	Repeat the above procedure for the remaining dust seals.

4. Remove the brake caliper from the vise.

Note: Do not damage the dust seal.

5. Using a small plastic tool, position the dust seal in the groove of the brake caliper piston.
6. Install the front brake caliper. Refer to Front Brake Caliper Replacement.

Front Brake Caliper Overhaul JL9, J55

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.

1. Remove the front brake caliper from the vehicle. Refer to Front Brake Caliper Replacement.
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.

Note: 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.

Caution: Refer to Fastener Caution in the Preface section.

16. Install the caliper bleed screw and tighten 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.