Why is the brake very hard when starting the car?
2 Answers
The reasons why the brake is very hard when starting the car are as follows: 1. Reason one: It is related to stepping on the brake before turning off the engine; the car's braking system can only function at its maximum when the engine is running, and the brake booster pump is the driving force behind the vehicle's braking. The force applied to the pedal is amplified by it. When the engine is off, the brake booster pump also stops running. Generally, stepping on the brake pedal three times will exhaust its remaining vacuum force, so the hard brake feeling is actually due to the lack of operation of the brake booster pump. 2. Reason two: The car's brake booster pump is leaking or malfunctioning. If you did not step on the brake pedal after turning off the car, or if you find the brake pedal very hard to press while driving, it is likely due to a fault in the brake booster pump, possibly caused by a vacuum tube leak or blockage. 3. Reason three: No antifreeze was added. Some car owners add water or low-quality antifreeze to their cars, resulting in extremely cold winter conditions that freeze the entire water circuit, crack the engine, cause the car's water pump to fail to operate, prevent the car from starting, and damage other engine components.
I've encountered a similar issue before where the brake pedal was extremely hard to press when starting the car. This is mainly because the brake booster system failed. When the engine isn't running, the vacuum booster doesn't receive vacuum assistance, relying solely on manual operation, which makes it feel particularly stiff. Possible root causes include vacuum line leaks, booster pump damage, or insufficient brake fluid. I recommend starting the engine first and then testing the brakes again. If they're still hard, you'll need to inspect the entire vacuum system, such as checking for cracks in the hoses or loose connections. Safety comes first—if this happens frequently, the brakes might not be responsive enough in emergencies, so it's best to get it diagnosed at a professional repair shop as soon as possible. Don't delay too long. Regularly check the brake fluid level and the condition of the lines to minimize potential risks.
