REMOVAL & INSTALLATION
See Figures 1, 2, 3, 4, 5, 6 and 7
- Remove the hub cap and loosen the lug nuts.
- Raise the front of the truck and safely support it with jackstands.
- Remove the lug nuts and the wheel.
- Attach a clear vinyl tube onto the bleeder plug on the brake cylinder, and insert the other end into a jar half filled with brake fluid. Bleed off a small amount of brake fluid.
- Disconnect and plug the brake line.
- Remove the caliper slide pin bolts and lift out the caliper.
- Press the caliper piston(s) back into the housing until they are flush and then install the caliper. Tighten the mounting bolts to 16-23 ft. lbs. (22-31 Nm) on 1984-86 models (720D series); and 53-72 ft. lbs. (72-97 Nm) on 1978-83 models and all 1986-88 models (D21-D series).
See Figures 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 and 191978-83
- Remove the caliper.
- Remove the pads.
- Remove the gripper pin attaching nuts and separate the yoke from the caliper body.
- Remove the yoke holder from the piston and remove the retaining rings and dust seals from the ends of both pistons.
- Apply air pressure gradually into the fluid chamber of the caliper, to force the pistons from the cylinders.
- Remove the piston seals.
- Inspect the parts for wear or damage. Check the inside surface of the cylinder for scoring or wear, and replace the caliper as necessary. Minor damage can be cleaned up with crocus cloth, buy deep pitting or scoring warrants replacement of the caliper. The piston should be examined for wear, but do not polish it with crocus cloth; it has a plated surface which will be damaged by sanding. Replace the piston as necessary.
- To assembly, coat the seals and pistons with clean brake fluid. Install the seals into the cylinder bore.
- Slide the A piston into the cylinder, followed by the B piston, so that its yoke groove coincides with the yoke groove of the cylinder.
- Install the dust seal and secure tightly with the retaining ring.
- Install the yoke holder onto the A piston and install the gripper to the yoke. If you lightly coat the gripper pins with soapy water, they will be easier to install.
- Support the end of the B piston, and press the yoke into the yoke holder. This will require a good deal of force. Be careful to insert the yoke straight into the holder, to avoid cracking the yoke holder.
- Install the pads, anti-squeal springs, and pad pins and retain with the clip.
- Tighten the gripper pin attaching nuts to 12-15 ft. lbs. (16-21 Nm), and install the caliper on the spindle.
- Raise and support the truck on jackstands.
- Remove the wheels.
- Remove the caliper pin bolts and lift off the caliper.
- Remove the brake pads.
- Disconnect and cap the brake hose.
- Remove the caliper pins and separate the cylinder body from the torque member.
- Remove the dust cover.
- Using compressed air, such as a portable compressor, place the air nozzle in the brake line hole and force the piston out of the cylinder body. It's a good idea to place a piece of wood in the cylinder body to cushion the piston as it leaves the cylinder. Wear safety goggles, as some brake fluid may be sprayed out.
- Remove the piston seal from its groove in the cylinder.
- Clean all parts in clean brake fluid. Check the cylinder bore and piston for wear, scratches and scoring. Minor rust and scratches in the cylinder bore may be removed with fine emery cloth. Any other damage will necessitate the replacement of the affected cylinder body. Any cracks in the torque member will require replacement of the part. The piston sliding surface is plated.
DO NOT USE EMERY CLOTH OR ANY OTHER POLISHING MATERIAL TO REMOVE RUST OR OTHER FOREIGN MATTER.
- Replace the piston seal and dust boot. If the support pins are damaged at all, replace them.
- Assembly is the reverse of disassembly. Coat all metal parts with clean brake fluid prior to assembly. Apply a thin coating of silicone brake lubricant to the support pins and bushings. Tighten the pin bolts.