Why Can't the Brake Be Pressed When Starting the Car?
3 Answers
There are two main reasons why the brake feels very hard to press in winter: one is a problem with the vacuum booster pump, making it difficult to press the brake without assistance. The other scenario is when the brake is pressed after the engine is turned off, exhausting the vacuum created by the vacuum booster pump, leaving only manual force to press the brake. Below is relevant information: 1. Related to pressing the brake before turning off the engine: The car's braking system works most effectively when the engine is running, and the brake booster pump is the key component that amplifies the force applied to the pedal. When the engine is off, the brake booster pump stops functioning, and typically, pressing the brake pedal three times will deplete its remaining vacuum force, making the brake feel hard without its assistance. 2. Brake booster pump air leakage: If the brake pedal is hard to press without having pressed it after turning off the engine, or if this issue is noticed while driving, it is likely due to a malfunction in the brake booster pump. This could be caused by a leak or blockage in the vacuum tube of the brake booster pump.
I've encountered the issue of the brake pedal being hard to press when starting the car several times, which is actually quite common. The main reason is that the engine hasn't started yet, so the brake booster pump lacks vacuum assist, making the pedal stiff. You need to understand that this isn't a malfunction, but part of the car's design. Most vehicles have stiff brakes before starting because the hydraulic system isn't operational with the engine off, causing the power assist to disappear. If you force it when the pedal won't budge and try to start the engine, it might not start and could potentially damage the battery or starter motor. My suggestion is not to panic—try pressing the brake pedal a few more times as it might regain some flexibility. Alternatively, check the battery charge; an old battery might prevent the car from starting. For prevention, have the battery and brake system tested during regular maintenance, especially in colder winter months. In short, this isn't a major issue, but mishandling it could lead to trouble.
This time when I was driving, the brake pedal was also hard to press, and I was sweating with anxiety. The reason was that the engine wasn't started, so there was no power assist for the brakes, making it feel like stepping on a hard rock. In my case, the battery was dead, and after trying to start the car for a long time without success, I realized the issue. Later, replacing the new battery solved the problem. If you encounter this situation in a parking lot, don't worry too much. You can ask a friend to help push the car or check the ignition system. For prevention, pay more attention to the smoothness of starting the car. If the car has been parked for a long time, the battery drains quickly, making this issue more likely to occur. Remember, safety first—don't force the car to start.
