Before starting the car, you will feel that the brake pedal is fairly “hard”, that is, it takes more force to push down. This mainly involves an important part of the brake system – the brake booster, which can only work when the engine is running.
The commonly used brake booster is a vacuum booster, and the vacuum area in the booster can be generated only when the engine is running. At this time, because the other side of the booster is atmospheric pressure, the pressure difference is formed, and we will feel relaxed when applying force. However, once the engine is turned off and the engine stops working, the vacuum will slowly disappear. Therefore, although the brake pedal can be easily pressed to produce braking when the engine is just turned off, if you try it many times, the vacuum area is gone, and there is no pressure difference, the pedal will become difficult to press.
The brake pedal suddenly stiffens
After understanding the working principle of the brake booster, we can understand that if the brake pedal suddenly stiffens when the vehicle is running (the resistance increases when stepping on it), then it is likely that the brake booster is out of order. There are three common problems:
(1) If the check valve in the vacuum storage tank in the brake power system is damaged, it will affect the generation of the vacuum area, making the vacuum degree insufficient, the pressure difference becomes smaller, thus affecting the function of the brake power system, making the resistance increase (not as normal). At this time, the corresponding parts need to be replaced in time to restore the function of the vacuum area.
(2) If there is a crack in the pipeline between the vacuum tank and the brake master pump booster, the result is similar to the previous situation, the vacuum degree in the vacuum tank is insufficient, affecting the function of the brake booster system, and the pressure difference formed is smaller than normal, making the brake feel hard. Replace the damaged pipe.
(3) If the booster pump itself has a problem, it can not form a vacuum area, resulting in the brake pedal is difficult to step down. If you hear a “hiss” leakage sound when you press the brake pedal, it is likely that there is a problem with the booster pump itself, and the booster pump should be replaced as soon as possible.
The problem of brake system is directly related to driving safety and can not be taken lightly. If you feel that the brake suddenly hardens during driving, you must cause enough vigilance and attention, go to the repair shop in time for inspection, replace the faulty parts, and ensure the normal use of the brake system.
Post time: Sep-30-2024