What to do when the brake suddenly becomes hard and cannot be pressed down during startup?

[LauraLee]

Here are the reasons and solutions for the sudden hardness and difficulty in pressing the brake 1. Related to pressing the brake before turning off the engine; The car's braking system works best when the engine is running, and the brake booster pump is the key component that amplifies the force applied to the pedal. Solution: In this case, simply restart the engine and try pressing the brake pedal firmly again. Once the engine is running, the brake booster pump will resume functioning, and the brake pedal will return to normal. 2. The car's brake booster pump is leaking or malfunctioning. If you did not press the brake pedal after turning off the engine, or if you notice the brake pedal is hard to press while driving, it is likely due to a faulty brake booster pump. Solution: If this issue is noticed before driving, it is advisable not to proceed and to have the car inspected at a repair shop immediately. If the problem occurs while driving, stay calm and prioritize slowing down to a stop. Try pressing the pedal multiple times to see if braking can be restored. Applying more force usually helps engage the brakes.