On ABS equipped models, the vacuum in the vacuum booster must be pumped down prior to removing the Brake Master Cylinder to prevent foreign matter from being sucked into the vacuum booster. With the ignition switch off, pump the brake pedal 4 to 5 times until a firm pedal is achieved without vacuum assist. Place rags under the
Brake Line fittings and prepare caps or plastic bags to cover the ends of the lines once disconnected, taking care to cover all painted surfaces to avoid damage from brake fluid. Unhook the clip and unplug the electrical connector from the brake fluid level sensor. Loosen the tube nuts at the ends of the brake lines entering the Brake Master Cylinder using a flare-nut wrench to prevent rounding off the flats on these nuts. Pull the brake lines away slightly and plug the ends to prevent contamination, also plugging the openings in the Brake Master Cylinder to prevent fluid spillage. Clean the area where the Brake Master Cylinder attaches to the vacuum booster with aerosol brake cleaner, then remove the two Brake Master Cylinder mounting nuts and take the Brake Master Cylinder out of the vehicle. Remove the reservoir cap and discard any remaining fluid. Bench bleed the Brake Master Cylinder before installation by mounting it in a vise and attaching a pair of bleeder tubes to the outlet ports. Fill the reservoir with the recommended brake fluid and slowly push the pistons into the Brake Master Cylinder using a large Phillips screwdriver to expel air into the reservoir. Repeat until no more air bubbles are present, then remove the bleed tubes one at a time and install plugs in the open ports to prevent leakage and air entry, followed by installing the reservoir cap. Install the Brake Master Cylinder over the studs on the power
Brake Booster and tighten the nuts finger-tight. Thread the front brake line fittings into the Brake Master Cylinder and the rear lines into the proportioning valves, ensuring the Brake Master Cylinder remains slightly loose for easier fitting. Tighten the Brake Master Cylinder mounting nuts to the specified torque and securely tighten the brake line tube nut fittings. Fill the Brake Master Cylinder reservoir with fluid, then bleed the Brake Master Cylinder and the rest of the brake system by having an assistant depress the brake pedal while loosening the fitting to allow air and fluid to escape, repeating this on other fittings until the fluid is free of air bubbles. Reinstall any components removed for access to the Brake Master Cylinder, re-check the brake fluid level, and carefully check the operation of the brake system before driving the vehicle in traffic.