GM 20990924 Cylinder Kit, Brake Master

You can Select Your Vehicle to check if 20990924 fits your vehicle.

To remove the brake master cylinder, start by disconnecting the cable from the negative terminal of the battery. Then, move the engine compartment fuse/relay box aside if necessary. Use a syringe or turkey baster to remove as much fluid as possible from the reservoir, being careful not to introduce air into the brake hydraulic system. Place rags under the fluid fittings and prepare caps or plastic bags to cover the ends of the lines once they are disconnected. Loosen the fittings at the ends of the brake lines where they enter the brake master cylinder using a flare-nut wrench. Pull the brake lines slightly away from the brake master cylinder and plug the ends to prevent contamination. Disconnect the electrical connector at the brake fluid level switch on the brake master cylinder reservoir and remove the nuts attaching the brake master cylinder to the power booster. Pull the brake master cylinder off the studs and out of the engine compartment, being cautious not to spill any fluid. If needed, transfer the reservoir to the new brake master cylinder by driving out the retaining pins and removing the reservoir directly up. To install the new brake master cylinder, begin by bench bleeding it. Mount the brake master cylinder in a vise and attach a pair of brake master cylinder 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 from the pressure chambers. Repeat this process until no more air bubbles are present. Remove the bleed tubes one at a time and install plugs in the open ports to prevent fluid leakage and air from entering. Install the reservoir cap. Place the brake master cylinder over the studs on the power brake booster and tighten the attaching nuts finger tight. Thread the brake line fittings into the brake master cylinder by hand and tighten them securely. Connect the brake fluid switch electrical connector and fill the brake master cylinder reservoir with fluid. To bleed the cylinder on the vehicle, have an assistant depress the brake pedal and hold it to the floor. Loosen the fittings to allow air and fluid to escape, then close the fittings. Repeat this procedure on both fittings until the fluid is clear of air bubbles. Reinstall the fuse/relay box and reconnect the battery. Finally, test the operation of the brake system carefully before placing the vehicle into normal service.

Place rags under the fluid fittings and prepare caps or plastic bags to cover the ends of the lines once they are disconnected.