What is the reason for a clunking sound when the brake is fully depressed?
2 Answers
The reasons for a clunking sound when the brake is fully depressed are: 1. Excessive wear of the brake disc and brake pads; 2. Issues with brake pad installation; 3. Rust on the brake disc or brake pads; 4. Use of low-quality or overly hard brake pads; 5. Abnormal brake caliper or lack of brake fluid; 6. Presence of foreign objects between the brake drum or disc and the brake shoes. Solutions for the clunking sound when the brake is fully depressed: 1. Apply butter or specialized lubricant at the connection between the brake pads and brake caliper; 2. Regularly inspect and replace brake pads; 3. Periodically adjust the brakes; 4. Avoid frequent use of brakes; 5. Re-adjust and reinstall the brake pads.
As a driver who frequently takes long-distance trips, I've seen this kind of issue many times. The most common cause of a clunking sound when braking hard is the ABS activating, especially during emergency braking when the anti-lock system rapidly releases pressure, creating a continuous noise—this is a normal protective mechanism. Another possibility is severely worn brake pads; when they wear down to the warning tabs, they produce a sharp alarm sound during hard braking. Additionally, chassis components can also cause trouble, such as worn control arm bushings that create gaps, leading to knocking sounds during sudden braking. The most dangerous scenario is air in the brake lines—insufficient hydraulic pressure when braking hard can cause abnormal noises along with increased stopping distance. Don’t try to fix these issues yourself; it’s best to take the car to a repair shop and have a mechanic inspect it on a lift. After all, safety is no small matter.
