Rear Disc Brake Caliper

DISASSEMBLY - CALIPER GUIDE PIN BUSHINGS (DISC/DISC BRAKES)

Before disassembling the brake caliper, clean and inspect it.
1. Using your fingers, collapse one side of the rubber guide pin bushing. Pull the guide pin bushing out the other side of the brake caliper mounting boss.

2. Repeat this procedure on the remaining bushing.

DISASSEMBLY - REAR CALIPER PISTON AND SEAL

WARNING: UNDER NO CONDITION SHOULD HIGH PRESSURE AIR EVER BE USED TO REMOVE A PISTON FROM A CALIPER BORE. PERSONAL INJURY COULD RESULT FROM SUCH A PRACTICE.

NOTE: Before disassembling the brake caliper, clean and inspect it.

NOTE: The safest way to remove the piston from the caliper bore is to use the hydraulic pressure of the vehicle's brake system.

1. Following the removal procedure, remove the caliper from the brake rotor and hang the assembly on a wire hook away from rotor and body of the vehicle so brake fluid cannot get on these components. Remove the brake shoes, and place a small piece of wood between the piston and caliper fingers.

2. Carefully depress the brake pedal to hydraulically push piston out of its bore. Once completed, apply and hold down the brake pedal to any position beyond the first inch of pedal travel using a brake pedal holding tool. This will prevent the fluid in the master cylinder reservoir from completely draining out.

3. Disconnect the brake fluid flex hose from the caliper assembly and remove it from the vehicle.

CAUTION: Do not use excessive force when clamping caliper in vise. Excessive vise pressure will cause bore distortion.

4. Mount the caliper in a vise equipped with protective jaws.

Fig. 10 Dust Boot Removal:

5. Remove the piston dust boot from the caliper and discard.

NOTE: Do not use a screw driver or other metal tool for seal removal. Using such tools can scratch the bore or leave burrs on the seal groove edges.





6. Using a soft tool such as a plastic trim stick, work the piston seal out of its groove in caliper piston bore. Discard the old seal.

7. Clean the piston bore and drilled passage ways using alcohol or a suitable solvent. Wipe it dry using only a lint-free cloth.

8. Inspect the piston bore for scoring or pitting. Bores that show light scratches or corrosion can usually be cleared of the light scratches or corrosion using crocus cloth.

CLEANING - CALIPER

WARNING: DUST AND DIRT ACCUMULATING ON BRAKE PARTS DURING NORMAL USE MAY CONTAIN ASBESTOS FIBERS FROM PRODUCTION OR AFTERMARKET BRAKE LININGS. BREATHING EXCESSIVE CONCENTRATIONS OF ASBESTOS FIBERS CAN CAUSE SERIOUS BODILY HARM. EXERCISE CARE WHEN SERVICING BRAKE PARTS. DO NOT SAND OR GRIND BRAKE LINING UNLESS EQUIPMENT USED IS DESIGNED TO CONTAIN THE DUST RESIDUE. DO NOT CLEAN BRAKE PARTS WITH COMPRESSED AIR OR BY DRY BRUSHING. CLEANING SHOULD BE DONE BY DAMPENING THE BRAKE COMPONENTS WITH A FINE MIST OF WATER, THEN WIPING THE BRAKE COMPONENTS CLEAN WITH A DAMPENED CLOTH. DISPOSE OF CLOTH AND ALL RESIDUE CONTAINING ASBESTOS FIBERS IN AN IMPERMEABLE CONTAINER WITH THE APPROPRIATE LABEL. FOLLOW PRACTICES PRESCRIBED BY THE OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION (OSHA) AND THE ENVIRONMENTAL PROTECTION AGENCY (EPA) FOR THE HANDLING, PROCESSING, AND DISPOSING OF DUST OR DEBRIS THAT MAY CONTAIN ASBESTOS FIBERS.

To clean or flush the internal passages of the brake caliper, use fresh brake fluid or Mopers Non-Chlorinated Brake Parts Cleaner. Never use gasoline, kerosene, alcohol, oil, transmission fluid or any fluid containing mineral oil to clean the caliper. These fluids will damage rubber cups and seals.

INSPECTION - CALIPER
Inspect the disc brake caliper for the following:

^ Brake fluid leaks in and around boot area and inboard lining

^ Ruptures, brittleness or damage to the piston dust boot

^ Damaged, dry or brittle guide pin dust boots

If caliper fails inspection, disassemble and recondition caliper, replacing the seals and dust boots.

ASSEMBLY - CALIPER GUIDE PIN BUSHINGS (DISC/DISC BRAKES)
1. Fold the guide pin bushing in half lengthwise.

NOTE: To avoid damage to the bushing, do not use a sharp object to install the guide pin bushing.

2. Insert the folded bushing into the caliper mounting boss using your fingers from the rear of the caliper.

3. Unfold the bushing using your fingers or a wooden dowel until the bushing is fully seated into the caliper housing. The bushing flanges should be seated evenly on both sides of the bushing hole.

4. Lubricate inside surfaces of bushing using Mopers Dielectric Grease or equivalent.

5. Repeat the procedure for remaining bushing.

ASSEMBLY - CALIPER PISTON AND SEAL

NOTE: Never use an old piston seal.

Installing New Piston Seal In Caliper:

1. Dip the new piston seal in clean brake fluid and install it in the groove of the caliper bore. The seal should be started at one area of the groove and gently worked around and into the groove using only your clean fingers to seat it.

2. Coat the new piston boot with clean brake fluid leaving a generous amount inside the boot.

3. Position the dust boot over the piston after coating it with brake fluid.

CAUTION: Force applied to the piston to seat it in the bore must be applied uniformly to avoid cocking and binding of the piston.

Installing Piston Into Caliper Bore:

4. Install piston into caliper bore pushing it past the piston seal until it bottoms in the caliper bore.

5. Position the dust boot into the counterbore of the caliper assembly piston bore.





6. Using a hammer and Installer, Special Tool C-4689 or C-4842 (depending on piston size), and Handle, Special Tool C-4171, drive the boot into the counterbore of the caliper as necessary.

7. Reinstall the caliper on the vehicle and bleed the brakes as necessary.