What Causes the Brake Pedal to Be Too Hard to Press Down?
3 Answers
The reason why the brake pedal is too hard to press down is due to air leakage or failure of the car's vacuum booster pump. Below is relevant information about brakes: 1. Precautions: To prevent "jerky" braking, if the braking distance is sufficient, you can slowly and steadily press the brake pedal to decelerate. When the car is about to stop, you can gently release the brake pedal until the car comes to a complete stop. 2. Braking on slopes: Braking on uphill sections is similar to braking on flat roads—both require gently pressing the brake pedal. However, the release should be quicker than on flat roads. On downhill sections, avoid prolonged braking as it can easily overuse the brake friction pads, reducing their effectiveness. Instead, use intermittent braking (pump braking) to decelerate and bring the car to a stop.
I had the same problem with my car last time, and it scared me so much that I rushed to get it checked. The mechanic said the most common issue is a faulty vacuum booster pump, which is connected to the engine intake manifold. If there's a leak or a broken pipe, it won't be able to pull the brake pedal. Another thing is that stepping on the brake several times when the engine is off can deplete the stored vacuum, making the pedal as hard as a rock. If the pedal becomes hard after a few normal presses when the engine is off but immediately recovers when the engine is running, it's most likely a problem with the booster pump. It's advised not to drive under such conditions and to tow it to a repair shop for inspection, as safety is not something to be taken lightly.
Our car enthusiast group's experienced drivers have analyzed this type of issue: Brakes becoming hard and difficult to press usually indicates an abnormality in the booster system. A cracked vacuum booster diaphragm or a failed check valve can both lead to insufficient vacuum. Additionally, a collapsed brake hose or a seized master cylinder piston may also fail to transmit pressure. Focus on checking whether the vacuum hose is loose or cracked, especially in older vehicles where rubber components are prone to aging. Owners who have modified their brakes should pay attention to whether the vacuum hose layout is reasonable. I remember last time when driving a friend's performance car, the brakes were hard to press right after starting, and it turned out to be a leaking vacuum tank.
