1. Autos

Your suggestion is on its way!

An email with a link to:


was emailed to:

Thanks for sharing About.com with others!

DIY: How To Replace/Rebuild A Brake Master Cylinder
The brake master cylinder, indeed the whole brake system, is probably the most important part of your vehicle. It is a fairly easy job to replace or rebuild and something a beginner can easily do.
 More of this Feature
Before You Start
The Brake Master Cylinder
Rebuild The Master Cylinder
• Bleeding The Brake System
 Join the Discussion
"Car wont start when wet"
"Problems after storage?"
 Related Resources
Brake Master Cylinder
DIY: Wheel Cylinders
Past Articles
Auto Repair Glossary
T/Shooting The Brake System
 From Other Guides
Motorcycle Recalls
Getting Started 4 Wheeling
2005 Infiniti QX 56 Test Drive
Comparison of Hybrid Cars
 Elsewhere on the Web
Motor Trend Magazine
Hot Rod Magazine
Bleeding The Brake System

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.

Refer to figures 3 and 4 when performing the following procedures.

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.

Next page» Before You Start » Page 1, 2, 3, 4, 5, 6

Additional information provided courtesy of ALLDATA

© 2004 Vincent T. Ciulla

©2017 About.com. All rights reserved.