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.
Before installing the new master cylinder on the vehicle, it must first be bled using a specialized bleeder kit. The master-cylinder bleeder kit comes with tubing, clips and multiple adapters. Most new or rebuilt master cylinders come with a bleeder kit for that particular master cylinder.
- Begin by removing the cap.
- Follow the directions that come with the kit to select the suitable adapters, and then connect the adapters and tubes to the ports on the cylinder. The other ends of the tube extend down into the master cylinder, and are held in place by a plastic clip. Figure 2.
- With the bleeder kit installed, fill the master cylinder about halfway with new brake fluid. Use a large screwdriver to depress the valve assembly inside the master cylinder. If you do not have a vise you can mount the master cylinder on the vacuum brake booster and bleed the master cylinder.
- Small bubbles will appear in the fluid. Continue working the valve assembly until no more bubbles appear. This indicates that the cylinder has been thoroughly bled.
Fig. 2. Bench Bleeding The Master Cylinder
- Reverse the removal procedure to install the master cylinder, noting the following:
- Refer to your service manual for any Master Cylinder Push Rod Adjustment procedures if your vehicle requires it.
- Bleed brakes as described under Brake Bleeding.
- Operate the brakes several times and check for external hydraulic leaks.
This is fairly straightforward job. Replacing a master cylinder should take you about 1 to 2 hours, depending on the make and model of car. If you are rebuilding the master cylinder, add about another hour or so.
Rebuild The Master Cylinder
Additional information provided courtesy of ALLDATA
© 2004 Vincent T. Ciulla