Rear 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 rear brake caliper. Refer to Rear 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 rear brake caliper. Refer to Rear Brake Caliper Replacement.

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

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.

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).

Note: 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.

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 Rear Brake Caliper Replacement.