Rear Disc Brake Caliper
DISC BRAKE CALIPERS - REARREMOVAL
1. Using a brake pedal holding tool as shown (Fig. 70), depress the brake pedal past its first one inch of travel and hold it in this position. This will isolate the master cylinder from the brake hydraulic system and will not allow the brake fluid to drain out of the master cylinder reservoir while the lines are disconnected.
2. Raise the vehicle.
3. Remove the rear tire and wheel assembly.
4. Remove the banjo bolt connecting the brake hose to the brake caliper (Fig. 71). There are two washers (one on each side of the flex hose fitting) that will come off with the banjo bolt. Discard these washers. Replace them with new ones.
NOTE: In some cases, it may be necessary to retract the caliper piston in its bore a small amount in order to provide sufficient clearance between the shoes and the rotor to easily remove the caliper from the knuckle. This can usually be accomplished before the guide pin bolts are removed, by grasping the rear of the caliper and pulling outward working with the guide pins, thus retracting the piston. Never push on the piston directly as it may get damaged.
5. Remove the two caliper guide pin bolts (Fig. 72).
6. Remove the caliper assembly from the brake adapter by first rotating the top of the caliper away from the rotor, and then lifting the caliper assembly off the machined abutment on the adapter (Fig. 73).
DISASSEMBLY (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 (Fig. 74).
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 (Fig. 75).
DISASSEMBLY (PISTON AND SEAL)
Before disassembling the brake caliper, clean and inspect it.
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: The safest way to remove the piston from the caliper bore is to use the hydraulic pressure of the vehicle's brake system.
1. 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.
CALIPER SEAL REMOVAL
CAUTION: Do not use excessive force when clamping caliper in vise. Excessive vise pressure will cause bore distortion.
1. To disassemble the caliper, mount it in a vise equipped with protective jaws.
2. Remove the piston dust boot from the caliper and discard (Fig. 76).
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.
3. Using a soft tool such as a plastic trim stick, work the piston seal out of its groove in caliper piston bore (Fig. 77). Discard the old seal.
4. Clean the piston bore and drilled passage ways using alcohol or a suitable solvent. Wipe it dry using only a lint-free cloth.
5. 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 the equivalent to hone the bore. Do not over-hone the bore. Do not increase the diameter of the bore more than 0.0254 mm (0.001 inch) (Fig. 78). 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.
6. 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 - DISC BRAKE 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 - DISC BRAKE 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 (GUIDE PIN BUSHINGS)
1. Fold the guide pin bushing in half lengthwise at the solid middle section (Fig. 79).
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 (Fig. 80).
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 (Fig. 81).
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 (Fig. 82).
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 (Fig. 82). 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 (Fig. 83). 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 (PISTON AND SEAL)
NOTE: Never use an old piston seal.
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 (Fig. 84) 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.
4. Install piston into caliper bore pushing it past the piston seal until it bottoms in the caliper bore (Fig. 85).
5. Position the dust boot into the counterbore of the caliper assembly piston bore.
6. Using a hammer and Installer, Special Tool C-4689, and Handle, Special Tool C-4171, drive the boot into the counterbore of the caliper (Fig. 86).
7. Install the brake shoes.
8. Reinstall the caliper on the vehicle and bleed the brakes as necessary.
INSTALLATION
CAUTION: When installing new brake components, be sure to use correct parts. Parts designed for BR3 Performance Brake System must not be mixed with other brake systems. These parts, similar in appearance, can be easily identified.
NOTE: Step (1) below is only required when installing the disc brake caliper after new brake shoes have been installed.
1. Completely retract the caliper piston back into piston bore of the caliper.
2. Lubricate both adapter caliper slide abutments with a liberal amount of Mopar Multi-purpose Lubricant, or an equivalent.
CAUTION: Use care when installing the caliper assembly onto adapter so the guide pin bushings and sleeves do not get damaged by the mounting bosses on adapter.
3. Starting with the lower end, carefully lower the caliper and brake shoes over the brake rotor and catch the caliper's bottom edge behind the caliper slide abutment (Fig. 73). Rotate the top of the caliper into mounting position on the adapter.
CAUTION: Extreme caution should be taken not to cross thread the caliper guide pin bolts when they are installed.
4. Carefully install the caliper guide pin bolts (Fig. 72), then tighten them to a torque of 22 Nm (192 inch lbs.).
5. Install the banjo bolt connecting the brake hose to the brake caliper (Fig. 71). Install NEW washers with the banjo bolt. Place one fitting washer on each side of the hose fitting as the banjo bolt is guided through the fitting. Thread the banjo bolt into the caliper and tighten it to a torque of 24 Nm (210 inch lbs.).
6. Install the tire and wheel assembly. Tighten the wheel mounting nuts to a torque of 135 Nm (100 ft. lbs.).
7. Lower the vehicle.
8. Remove the brake pedal holding tool.
9. Bleed the caliper as necessary.
10. Road test the vehicle and make several stops to wear off any foreign material on the brakes and to seat the brake shoes.