One of the main components of an automobile's hydraulic braking system is the master cylinder, which is usually located in a vehicle's engine compartment. When you depress the brake pedal, a push rod activates a piston in the master cylinder, which sends brake fluid to all four wheels. A problem with the master cylinder could mean total loss of braking power for the vehicle. Most backyard mechanics can replace the master cylinder on their own with the right tools and know-how.
Instructions
- 1
Open the hood and locate the brake master cylinder, which is usually mounted on the driver's side of the firewall. Remove the master cylinder reservoir cap. Remove the brake fluid from the reservoir with a syringe.
2Remove the electrical connector from the master cylinder (if your vehicle is so equipped) by pressing in on the release tabs and pulling the connector straight out. Loosen the brake line retaining nuts at the base of the master cylinder with a tubing wrench.
3Loosen and remove the master cylinder retaining nuts at the firewall or brake booster with a socket and ratchet. Lift the master cylinder straight up from the engine bay.
4Place a replacement master cylinder in a bench vise with the reservoir opening facing up. Fill the master cylinder reservoir with brake fluid, but do not replace the cap.
5Obtain a master cylinder brake bleeding kit, which is available at auto parts stores. Thread the short hoses that came with the bleeder into the brake line fittings at the base of the master cylinder and tighten them with a tubing wrench. Place the other end of each hose into the master cylinder reservoir.
6Push the master cylinder piston in with a wooden dowel several times until no air bubbles can be seen escaping from the ends of the short hoses. Keep the ends of the hoses submerged in the reservoir. Refill the reservoir as needed during this procedure to keep the level at the full mark.
7Remove the short hoses from the master cylinder with a tubing wrench. Remove the master cylinder from the vise and place it into position in the engine bay. Tighten the mounting nuts with a socket and ratchet.
8Push the wiring connector (if equipped) back into place on the master cylinder until it snaps into place. Tighten the brake line retaining nuts onto the base of the master cylinder with a tubing wrench. Refill the reservoir with brake fluid until the level reaches the full line, if necessary. Replace the reservoir cap and close the hood. Push the brake pedal to test the operation of the brakes before driving the vehicle.
