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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
Removal
Installation
Rebuild The Master Cylinder
Bleeding The Brake System
 
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The Brake Master Cylinder

The brakes are one area where you do not want to cut corners. Any brake work must be done properly to maintain maximum brake efficiency. If you feel you are not up to the task, take it to a professional mechanic.

The brake master cylinder, indeed the whole brake system, is probably the most important part of your vehicle. As I have always said, there is no sense in making the car go if you can't make it stop. As logical as this sounds, I have had customers come in and forego brake work in favor of improving their stereo systems or fancy wheels and tires. They probably want to listen to music and look good in a wreck while they wait for the ambulance to come and take them to the hospital.

Most modern car braking systems are broken into two circuits, with two wheels on each circuit to increase safety. In most vehicles it is one front wheel and one rear wheel although some vehicles split front and rear wheels. With a dual system like this, if a brake fluid leak occurs in one circuit, you only lose 50% of your brakes. You will be able to stop although it will take somewhat longer.

The master cylinder supplies pressure to both circuits of the car. It uses two pistons in the same cylinder in a way that supplies brake pressure to both circuits and it is very reliable. There is a combination valve that warns the driver, among other things, if there is a problem, such as a leak, with the brake system.

The brake system uses a special fluid to operate the system. Brake fluid is a specially formulated liquid used in the brake hydraulic system. Brake fluid must meet one of three U.S. Department of Transportation (DOT) specifications. DOT 3 and DOT 4 are glycol-based fluids, which absorb water. DOT 5 is a silicone-based fluid and does not absorb water. The main difference is that DOT 3 and DOT 4 absorb water, while DOT 5 doesn't. Most cars use DOT 3 fluid from the factory.

Okay, let's get to work!

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Additional information provided courtesy of ALLDATA

© 2004 Vincent T. Ciulla

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