Why Can't I Press the Brake and Start the Car?
4 Answers
The brake suddenly becoming hard to press might be because the owner stepped on the brake several times after turning off the engine, causing the vacuum in the brake booster pump to disappear. Without the booster's assistance, it becomes difficult to press the brake pedal. Additionally, the booster pump does not operate when the engine is off. In this case, simply attempt to restart the engine and press the brake pedal firmly. Once the car starts, the brake system should return to normal. Owners should also pay attention to proper braking techniques in daily driving: 1. During low-speed driving, emergency braking can be applied by firmly pressing the brake pedal when encountering sudden events ahead. However, this should not be done at high speeds to avoid vehicle skidding or rollover. 2. Under normal road conditions, gradual braking is recommended. Press the clutch pedal while releasing the accelerator pedal, shift to a lower gear, and then press the brake pedal until the vehicle comes to a complete stop after the speed has decreased. 3. On long downhill slopes in mountainous areas or during continuous braking where high temperatures are likely to occur, intermittent braking—alternately pressing and releasing the brake pedal—can effectively prevent the braking system from overheating.
I bet you're really anxious right now, this situation is the most annoying. The brake pedal being hard to press and causing the car not to start is most likely due to a problem with the vacuum booster. After we turn off the engine, it stops supplying air to the booster pump. If you've pressed the brake a few times before, the vacuum in the pump gets completely used up, making the brake pedal stiff. Another possibility could be a cracked vacuum tube leaking air or the engine itself not supplying enough air. Don't panic if you encounter this situation. First, try pressing the brake pedal hard with some force—sometimes, pressing it down firmly can still start the car. If that doesn't work, just call for roadside assistance. Don't go disassembling parts randomly; I've seen people blow fuses and make things even more troublesome. Usually, try to avoid pressing the brake after turning off the engine, and during maintenance, ask the mechanic to focus on checking the vacuum tube's seal—it can save you a lot of hassle.
I've encountered this issue before. During the morning rush hour, in a hurry to get to work, I got into the car only to find the brake pedal as hard as a rock and unresponsive when starting the engine. Later, I figured out it was due to the vacuum booster system failing. Repeatedly pressing the brake after the engine is turned off can deplete the vacuum reserve, causing the booster to fail and making the pedal hard to press. Additionally, a leaking brake fluid line or air entering the system can cause the same issue. In an emergency, you can try stomping hard on the brake pedal—sometimes a forceful press can get it working, but never attempt this on a slope as it's too dangerous. If that doesn't work, check the battery, as a weak battery can also trigger a chain of malfunctions. I recommend paying attention to the brake system's sealing during regular maintenance, especially inspecting the condition of the booster pump and vacuum hoses, as prevention is always better than cure.
Brake pedal too hard to press causing failure to start? Most likely the vacuum booster pump is to blame. After the car is turned off, the booster pump relies on residual vacuum to operate. If you pressed the brake after turning off the engine, the vacuum would be depleted, naturally making the pedal hard. It could also be due to air leakage in the pipes allowing air to enter. In this case, try stepping on the brake with all your might—some cars can start as long as the pedal sinks slightly. Also, check the battery condition, as insufficient voltage can affect the entire system. During maintenance, it's best to have the repair shop test the brake booster performance. Replacing a seal for just a few dozen bucks can prevent major trouble.
