Power brakes are the standard on just about every automobile on the road. Modern power brake systems can magnify the driver's 50-lb push on the brake pedal into something in the order of 1,000 lb of force at the brakes, and the brake system power booster is a vital part of this system. The power booster uses vacuum generated by the engine operation to assist the driver's force on the brake pedal and make braking a much easier task. Unfortunately, when problems arise with the power booster it can lead to a dangerous situation, and it is important for you to know how to verify the proper operation of the power booster.
Instructions
- 1
Pump the brake pedal a few times with the engine shut off. Depress the brake pedal and hold it down. Start the engine. The brake pedal should almost immediately drop slightly, and the pedal should change from a high and hard feel to a normal feel. If it does not then this indicates a problem with the brake power booster, or possibly a low engine vacuum or plugged vacuum hose.
2Run the engine for a few minutes. Turn the engine off and then immediately depress the brake pedal four or five times. The brake pedal should feel harder with each push, and it should come to a stop at a higher position each time. If the pedal returns to the same position each time then it indicates a problem with the brake power booster.
3Run the engine for a few minutes. Depress brake pedal and hold it down. Turn the engine off and keep the brake pedal depressed for 30 seconds of so. The brake pedal height should not change during this time. If the pedal rises it indicates a problem with the brake power booster.
