With the engine off, pump the brake pedal several times to deplete the vacuum in the power brake booster. Begin by removing the air filter housing cover and unplugging the electrical connector for the fluid level warning switch. Use a suction gun, large syringe, or poultry baster to remove as much fluid as possible from the reservoir, placing rags under the fittings and preparing caps or plastic bags to cover the ends of the lines once disconnected. Pull the brake lines away from the Brake Master Cylinder and plug the ends to prevent contamination. Remove the two nuts attaching the Brake Master Cylinder to the power booster, carefully pulling the Brake Master Cylinder off the studs while avoiding fluid spillage. Discard the old gasket between the Brake Master Cylinder and the power brake booster, and check the O-ring on the end of the Brake Master Cylinder, replacing it if cracked or hardened. Before installing a new or rebuilt Brake Master Cylinder, check the clearance between the booster pushrod and the pocket in the Brake Master Cylinder piston, adjusting the length of the power brake booster pushrod if necessary. Bench bleed the Brake Master Cylinder by mounting it in a vise and attaching a pair of bleeder tubes to the outlet ports, filling the reservoir with the recommended brake fluid. Slowly push the pistons into the Brake Master Cylinder to expel air into the reservoir, repeating until no more air bubbles are present. Remove the bleed tubes one at a time, installing plugs in the open ports to prevent leakage and air entry, then install the reservoir cap. Install the Brake Master Cylinder over the studs on the power brake booster, tightening the nuts only finger-tight and using a new gasket. Thread the brake line fittings into the Brake Master Cylinder, ensuring they thread in easily without stripping. Tighten the mounting nuts and brake line fittings securely, then plug in the electrical connector to the fluid level warning switch. Fill the Brake Master Cylinder reservoir with fluid, then bleed the Brake Master Cylinder and the brake system by having an assistant depress the brake pedal while loosening the fitting to allow air and fluid to escape, repeating until the fluid is clear of air bubbles. Check the operation of the brake system carefully before driving the vehicle. If the brake fluid reservoir becomes damaged or leaks between the reservoir and the Brake Master Cylinder body, it can be replaced separately, and the grommets on the reservoir can be replaced if necessary. Remove as much fluid as possible from the reservoir, placing rags under the Brake Master Cylinder to absorb any fluid that may spill out. Remove the screw retaining the reservoir to the Brake Master Cylinder, then drive out the roll pin with a hammer and punch. Pull the reservoir out of the Brake Master Cylinder body and remove the grommets, replacing them if they are hard, cracked, or damaged. Lubricate the new grommets with clean brake fluid, press them into place, push the reservoir into the grommets, and secure it with the screw. Refill the reservoir with the recommended brake fluid and check for leaks, then bleed the Brake Master Cylinder followed by the remainder of the system.
