There are several things that can cause a bad brake booster including a bad vacuum. A brake booster needs vacuum pressure to work effectively so a lack of pressure can cause failures. Other causes of booster failure include broken springs and ruptured diaphragms.
To ensure the vacuum is working properly, the car owner should first check to ensure all hoses on the brake system are in good shape and have no leaks. A vacuum gauge can also be used to determine if the booster is receiving an adequate amount of suction to properly function.
Broken springs and ruptured diaphragms can cause the brake pedal to not return to the proper position after it is pressed. These also commonly cause the brake light to stay on within the instrument panel. This can be checked by inspecting the brake system thoroughly.
To test the booster, users should press the brake with the vehicle turned off. After the brake starts becoming harder to push down, users should hold it down as far as possible and turn on the vehicle. If the booster is in good working order, the pedal will push further down as suction is created. When a brake booster, or any component of the brake system fails, repairs are vital for safety.