All Info About Auto Repairs
Your One Stop Source For All The Information You Need For Your Vehicles.

DIY: Replace/Rebuild A Brake Master Cylinder

The brake master cylinder, indeed the whole brake system, is probably the most important part of your vehicle.
» Before You Start
» Brake Master Cylinder
» Removal
» Installation
» Master Cylinder Rebuild
» Bleeding The Brakes

NOTE: Pressure bleeding is recommended for all hydraulic systems. However, if a pressure bleeder is unavailable, use the following procedure. Some hydraulic systems require vacuum bleeding. Check your vehicles service manual for the procedure.

CAUTION: Brake fluid damages painted surfaces. Immediately clean any spilled fluid.

  1. Remove the vacuum reserve by pumping the brakes several times with the engine off.
  2. Fill the master cylinder reservoir with clean brake fluid. Check the fluid level often during bleeding procedure; do not let the reservoir fall below half full.
  3. If necessary, bleed the master cylinder as follows:

    • Disconnect the master cylinder forward brake line connection until fluid flows from the reservoir. Reconnect and tighten the brake line.
    • Instruct an assistant to slowly depress the brake pedal one time and hold.
    • Crack open the front brake line connection again, purging air from the cylinder.
    • Retighten the connection and slowly release the brake pedal.
    • Wait 15 seconds and then repeat until all the air is purged.
    • Bleed the rearward brake line connection by repeating the preceding steps.
    • Loosen and then slightly retighten the bleeder valves at all four wheels. Repair any broken, stripped or frozen valves at this time.

Brake Master Cylinder
Fig. 5. Bleeding The Brake System
  1. Proceed to the appropriate wheel first and follow the set sequence according to the Wheel Bleed Sequence.
  2. Place a transparent tube over the bleeder valve and then allow the tube to hang down into a transparent container, figure 5. Ensure the end of the tube is submerged in clean brake fluid.
  3. Instruct an assistant to slowly depress the brake pedal one time and hold.
  4. Crack open the bleeder valve, purging air from cylinder. Retighten the bleeder screw and slowly release pedal.
  5. Wait 15 seconds and then repeat the preceding bleed steps. Repeat these steps until all the air is bled from the system.

Wheel Bleed Sequence:

If you are bleeding the brakes manually, the sequence is RR-LR-RF-LF. If you are pressure bleeding, bleed the front brakes together and the rear brakes together.

» Part 1       » Part 2       » Part 3       » Part 4
» Part 5       » Part 6

Additional Information provided courtesy of and Warranty Direct
© 2000-2007 Vincent T. Ciulla

FREE Newsletter. Sign Up Now!

Help keep this site free.

Copyright (c)2006

Search All Info About

Related Articles