Before beginning this procedure, purchase a brake caliper overhaul kit specific to your vehicle. For 1988 and earlier models, start by removing the caliper and placing it on a workbench, then take out the brake pads. Remove the shoe dampening spring from the caliper piston and secure the caliper in a vise, cushioning the interior. Work the piston out by moving the parking brake lever back and forth; if it resists, use a wrench to rotate the actuator screw until the piston is free. Remove the balance spring, retaining nut, lever, lever seal, and anti-friction washer. Press the actuator screw out, pry out the dust boot, and use a tool to remove the piston seal. If necessary, take out the banjo housing retaining bolt and housing. Inspect the caliper bore for damage and clean all parts not included in the repair kit with appropriate solvents. Dry the parts with compressed air, install the bleeder valve, and if applicable, the parking brake lever mounting bracket. Assemble the banjo housing with new copper washers, lubricate and install the new piston seal, boot, thrust washer, and shaft seal. Lubricate the actuator screw and install it in the piston, followed by the balance spring. Lubricate the piston and caliper bore, then insert the piston assembly. Use a piston compressor to push the piston in, lubricate the anti-friction washer and lever seal, and install the lever, tightening the retaining nut. Seat the boot in the caliper recess and install the dampening spring. For 1989 and later models, clean the caliper exterior, unhook the collar return springs, and remove the actuating collar. Separate the clamp rod and bushing, discard the bushing, and remove the boot retainers and boots. Replace the piston seal, inspect the caliper bore, and wash all reusable parts. Lubricate the piston bore and install the piston, then lightly lubricate the actuating collar and assemble the pushrod, boots, and retainers. Attach the preload spring, lubricate the clamp rod, and insert it into the actuator collar. Push a new bushing onto the clamp rod, lubricate the inner boot, and guide the components into the caliper. Install the collar return springs, lubricate the caliper guide pins, and check the guide pin boots. Install the brake pads and the caliper, then bleed the brakes. Adjust the parking brake free travel to ensure no binding occurs, measuring the clearance between the lever and caliper housing, which should be between 0.024 and 0.028 inch. If adjustments are needed, clean the adjusting screw threads, apply thread locking compound, and turn the screw to achieve the desired clearance, then re-check after having an assistant pump the brake pedal.
Posted by GMPartsGiant Specialist