Checking the brake booster (Mazda 121 (3))

The operation of the brake booster should be checked when the force on the brake pedal becomes unusually high.

With the engine not running, press the brake pedal at least 5 times, and then start the engine with the pedal pressed. The pedal should noticeably drop under the force of your foot.

You can also disconnect the vacuum hose from the brake booster and start the car. Place your finger on the free end of the hose to check if there is a vacuum.

If there is no vacuum, check the vacuum hose for leaks and damage and replace it if necessary. Tighten all clamps securely.

Diesel engine: remove the vacuum hose from the vacuum pump and check with your finger if there is vacuum at the pump outlet. If there is vacuum, measure the vacuum value, if necessary, replace the brake booster in a workshop.