Front Disc Brake Caliper
DISASSEMBLY - CALIPER GUIDE PIN BUSHINGS
Before disassembling the brake caliper, clean and inspect it.
1. With one hand, push the guide pin bushing sleeve towards the back of the caliper, and at the same time, pull the sleeve out the back of the caliper and bushing.
2. 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.
DISASSEMBLY - 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.
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.
Honing Brake Caliper Piston Bore:
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. Bores that have deep scratches or scoring should be honed. Use Caliper Hone, Special Tool C-4095 or equivalent, to hone the bore. Do not over-hone the bore. Don not increase the diameter of the bore more than 0.0254 mm (0.001 inch). If the bore does not clean up within this specification, a new caliper housing should be installed.
NOTE: During the honing procedure, coat the stones and bore with brake fluid. After honing the bore, carefully clean the seal and boot grooves with a stiff non-metallic rotary brush. Use extreme care in cleaning the caliper after honing. Remove all dirt and grit by flushing the caliper bore with fresh clean brake fluid; wipe it dry with a clean, lint free cloth and then clean it a second time.
9. Inspect the caliper piston for pitting, scratches, or any physical damage. Replace the piston if there is evidence of scratches, pitting or physical damage.
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 Mopar 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
Folded Caliper Guide Pin Bushing:
1. Fold the guide pin bushing in half lengthwise at the solid middle section.
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.
Bushing Correctly Installed In 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 the inside surfaces of the bushing using Mopar Dielectric Grease or an equivalent.
5. Install the guide pin sleeve into one end of bushing until the seal area of bushing is past the seal groove in the sleeve.
6. Holding the convoluted boot on the opposite end of the bushing, push the steel sleeve through the bushing until the bushing boot is fully seated into the seal groove on that end of sleeve. Install the other end bushing boot into the groove on that end of the bushing sleeve.
7. Verify both ends of the bushing are seated in the sleeve groves. When the sleeve is seated properly into the bushing, the sleeve/bushing can be held between your fingers and easily slid back and forth without the bushing unseating from the sleeve groove.
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 caliber if necessary.
7. Reinstall the caliper on the vehicle and bleed the brakes as necessary.