The Basics Of The Brake System

A Word of Wisdom: Check your vehicles brakes on every other oil change. Don't wait until you hear the squeaks or grinding noise of your brakes. This will save you money on replacements of the brake rotors.

Most cars have disc brakes up front and drum brakes in the rear. A few performance and luxury models have disc brakes in the front and rear.

• Foot effort applied to the brake pedal is amplified in most cars by a vacuum operated power assist unit.
• Simultaneously, the master cylinder pressurizes the brake fluid in two separate hydraulic circuits. One circuit serves the front brake calipers by restricting front brake units, and other serves the rear drums units.
• Simultaneously, the master cylinder pressurizes the brake fluid in two separate hydraulic circuits. One circuit serves the front brake calipers by restricting front brake units, and other serves the rear drums units.
• The combination valve contains a metering valve that controls pressure to the front brakes calipers by restricting the flow of the brake fluid to them until about 125 pounds per square inch of pressure has developed. This delays the front brake caliper action just long enough for the slower reacting rear brakes to engage.

The combination valve also houses a self-centering pressure differential sensing switch. Should the system develop a brake fluid leak, the switch will block off the hydraulic circuit where the leak has occurred. This switch may also illuminate a dashboard warning light.

Some systems have a proportioning valve, which balances the hydraulic pressure of the rear drum brake and helps control rear wheel skidding.

Learn more about these other systems...

The Starter System

The Ignition System

The Coolant System