What are the reasons for the sudden stiffness and inability to press the brake when reversing?
3 Answers
Here are the reasons for the sudden stiffness and inability to press the brake when reversing: Reason: One is a problem with the vacuum booster pump, making it difficult to press the brake without assistance. Another situation is that after the engine is turned off, the brake is pressed again, depleting the vacuum created by the vacuum booster pump, and subsequent braking relies solely on manual force. Related introduction to brakes: The brake is a mechanical braking device that can slow down the vehicle speed. Simply put: The car brake pedal is located under the steering wheel. Pressing the brake pedal causes the brake lever linkage to be pressurized and transmitted to the brake pads on the brake drum, clamping the brake disc to slow down or stop the car. The manual brake in a car is located next to the gear shift, connected to the brake lever.
I've been repairing cars for over 20 years and have seen many cases where the brakes become hard when reversing. Most of the time, it's due to a faulty vacuum booster or vacuum system. When the engine runs at low RPM during reversing, the vacuum supply is insufficient, causing the brake assist to fail and making the brakes as hard as a rock. Common causes include aging or cracked vacuum hoses, a clogged or leaking booster pump, which can make the issue apparent only when reversing despite normal driving conditions. During inspection, first check for loose connections or cracks at the vacuum hose joints, and try pumping the brakes a few times to see if they recover. If that doesn't work, take the car to a professional repair shop for instrument testing immediately. Safety comes first—never ignore this issue, as reversing often leads to scrapes, and failing to stop in time can have serious consequences. Regular maintenance and inspection of the brake system are recommended, especially for older cars where hoses are prone to aging; replacing them can prevent problems.
Last year when I was reversing into a parking space, the brake pedal suddenly became too hard to press, and I almost hit the wall, which gave me a cold sweat. Later, at the repair shop, they found a small crack in the vacuum booster system's pipe. When reversing at idle speed, the vacuum pressure wasn't sufficient, so the brake assist failed. Normally, when driving with the engine running faster, the issue wasn't noticeable. I learned the simple principle that brake assist relies on vacuum operation—if the pipe or booster is damaged, this can happen. It's advisable to listen for any hissing sounds under the hood that might indicate a leak. In an emergency, try pressing the brake pedal deeply a few times to see if it restores. This kind of failure is quite common, especially in older cars where rubber pipes can become brittle. A quick glance during car washes can help detect issues early. It's crucial to fix it promptly; otherwise, the next time you reverse, an accident could happen. Safety is no small matter.
