What are the symptoms of a faulty brake booster pump?
3 Answers
Symptoms of a faulty brake booster pump: air leakage in the brake pump, poor braking performance or no braking effect, visible oil leakage at the external connections of the vacuum pump, slow or non-returning brake pedal, noticeable abnormal noise when pressing the brake pedal, the vehicle pulling to one side or shaking during braking, and a soft feeling when pressing the brake pedal. The brake booster pump, also known as the brake assist pump, controls the vacuum entering the booster pump during braking, causing the diaphragm to move. Through a linkage device, the push rod on the diaphragm assists the driver in pressing and pushing the brake pedal, thereby amplifying the force applied by the driver.
When the brake booster fails, the brake pedal feels extremely stiff, requiring significant force to press down, as if pushing a heavy rock. Normally, a light tap would slow the car, but now you have to exert much more effort. Another symptom is a noticeably increased braking distance, especially during emergency stops, making it hard to halt the vehicle and increasing the risk of rear-end collisions. Sometimes, even after turning off the engine, the brake pedal remains stiff, whereas it should feel soft under normal conditions. If you hear a hissing sound or unusual noise when braking while driving, it could indicate a vacuum leak. Additionally, experiencing weak or ineffective braking at idle is another warning sign. From my repair experience, I’ve seen many older vehicles with this issue, and owners often complain about how exhausting it is to drive. For safety, if these symptoms appear, visit a professional repair shop as soon as possible—otherwise, encountering an emergency at high speeds could be disastrous.
Last time my car had an issue where the brakes became hard and almost impossible to press, nearly causing an accident. I didn’t pay much attention at first, but later discovered the brake booster pump was faulty. After starting the engine, the pedal was extremely heavy, slowing down was difficult, and I always felt powerless when stopping. Even after turning off the engine, the pedal remained stiff and never softened, accompanied by a slight hissing sound. Upon inspection, it was found that the vacuum hose had aged and was leaking. Since then, I’ve learned my lesson: always be vigilant for signs like sluggish brake response or increased pedal effort during daily driving. My advice is to slow down and pull over if you encounter similar issues—don’t force it. After timely replacement of the faulty parts and repairs, everything returned to normal, with safety as the top priority. These experiences taught me the importance of regular maintenance to avoid potential hazards.
