Master Cylinder: Reassembly
WARNING: This page does not describe the selected car, but rather 12 other vehicles, including the 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, and 2003 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Do not use abrasives to clean the brake master cylinder bore.
- Clean the interior and exterior of the master cylinder, the secondary piston, and the return spring in denatured alcohol, or equivalent. See Figure.
- Inspect the master cylinder bore, inlet and outlet ports, the secondary piston, and the return spring for cracks, scoring, pitting, and/or corrosion. Replace the master cylinder if any of these conditions exist.
- Dry the master cylinder and the individual components with non-lubricated, filtered air.
- Lubricate the master cylinder bore, the secondary piston, the return spring, and all of the individual overhaul components with Delco Supreme 11®, (GM P/N 12377967) or equivalent DOT-3 brake fluid from a clean, sealed brake fluid container.
- Assemble the lubricated, NEW primary seal and retainer, and NEW secondary seal onto the secondary piston.
- Install the lubricated return spring and secondary piston assembly into the cylinder bore.
- Install the lubricated, NEW primary piston assembly into the cylinder bore.
- Using a smooth, round-ended tool, depress the primary piston and install the NEW piston retainer.
- Install the master cylinder reservoir to the master cylinder. See MASTER CYLINDER RESERVOIR under REMOVAL & INSTALLATION.
- Install the reservoir cap and diaphragm to the reservoir.
- Install the master cylinder to the vehicle. See MASTER CYLINDER under REMOVAL & INSTALLATION.