Vacuum brake booster — check

The performance of the brake booster should be checked when an unusually high brake pedal force is required to achieve sufficient braking action.

1. Depress the brake pedal with force down to the stop at least five times with the engine off, then start the engine with the brake pedal depressed. Now the pedal under the foot should be noticeably moved down.

2. Disconnect the hose from the vacuum brake booster if the desired effect is not achieved.

3. Start the engine. Place your finger on the end of the hose to check for reduced pressure. If there is no reduced pressure, then check the condition of the vacuum hose and make sure it is not damaged. Replace hose if necessary. Tighten all hose clamps.

Diesel vehicles

4. Disconnect the hose from the vacuum pump to the brake booster and, by placing your finger on the end of the hose, check that there is low pressure that the pump should be producing.

If the pump creates low pressure, then measure it, and if necessary, replace the brake booster (In workshop).