If an overhaul is indicated, usually because of fluid leakage, it's important to explore all options before starting the job. It's possible to acquire new and factory rebuilt calipers on an exchange basis, which simplifies this process. In the event that it's decided to rebuild the calipers, it's crucial to have a rebuild kit available before proceeding. Always rebuild calipers in pairs, never just one of them. Begin by loosening the wheel lug nuts, raising the front of the vehicle, and supporting it securely on jackstands. Next, remove the front wheels, remove the brake hose inlet fitting bolt, and detach the hose. Have a rag ready to catch any spilled fluid and wrap a plastic bag tightly around the hose end to prevent fluid loss and contamination. Following this, remove the mounting bolts, detach the caliper from the vehicle and separate the pads from the caliper.To overhaul, clean the exterior of the caliper with brake cleaner or denatured alcohol, but never use gasoline, kerosene or petroleum-based cleaning solvents. Place the caliper on a clean workbench and carefully remove the ring retaining the dust boot to the caliper bore. Carefully pry the dust boot out of the caliper bore. Position a wood block or several shop rags in the caliper as a cushion, then use compressed air to remove the piston from the caliper. Use only enough air pressure to ease the piston out of the bore to avoid damage. Warning: Never place your fingers in front of the piston when applying compressed air, as serious injury could occur.Using a wood or plastic tool, remove the piston seal from the groove in the caliper bore. Metal tools may cause bore damage. Remove the caliper bleeder screw, then remove the sleeves and bushings from the caliper ears. Discard all rubber parts. Clean the remaining parts with brake system cleaner or denatured alcohol then blow them dry with compressed air.Examine the piston for nicks and burrs and loss of plating. Replace parts if surface defects are present. Check the caliper bore in a similar way. Light polishing with crocus cloth is permissible to remove light corrosion and stains. Discard mounting bolts if they're corroded or damaged.During assembly, lubricate the piston bore and seal with clean brake fluid. Position the seal in the caliper bore groove. Lubricate the piston with clean brake fluid, then install a new dust boot in the piston groove, with the fold toward the open end of the piston. Insert the piston squarely into the caliper bore, then apply force to bottom it. Position the dust boot in the cylinder groove and install the retaining ring. Install the bleeder screw. If the old bushings or pins will not clean up using crocus cloth, new ones should be installed. They should be lubricated with silicone grease. Install new rubber boots to the pins or bushings. Install the dust boot supports if equipped.To install, inspect the mounting bolts for excessive corrosion. Place the caliper in position over the disc and caliper mounting bracket, install the bolts and tighten them to the torque specifications. Install the brake hose and inlet fitting bolt, using new copper washers, then tighten the bolt. It's important to bleed the brakes afterward.Finally, install the wheels and lower the vehicle. After the job has been completed, firmly depress the brake pedal a few times to bring the pads into contact with the disc. Always check brake operation before driving the vehicle in traffic.
Posted by GMPartsGiant Specialist 
