What are the reasons for brake noise?
2 Answers
The reasons for brake noise are: severe tire wear, foreign objects on the brake pads, incorrectly installed or mismatched brake pads, and excessively thin brake linings. If a new car makes a squeaking noise when braking, it is a normal situation because new brake linings require a certain break-in period to increase the contact area between the brake pads and brake discs, achieving better braking performance. The Anti-lock Braking System (ABS) uses sensors installed on the wheels to send signals when the wheels are about to lock up. The controller then instructs the regulator to reduce the oil pressure in the wheel's brake cylinder, decreasing the braking torque. After a certain period, the original oil pressure is restored, and this cycle repeats continuously (up to 5 to 10 times per second), keeping the wheels in a rotating state while maintaining maximum braking torque.
Last time my old Jetta's brakes also started squeaking, so I specifically went to the repair shop to ask the master technician. He said that such high-frequency noise is mostly a warning sound from the brake pad wear indicator rubbing, indicating that the wear is nearing its limit. Additionally, small stones or metal debris getting stuck can also cause a harsh scraping sound, especially noticeable after rainy days. During that inspection, I also found that the edges of the brake discs had worn into a step, and the technician said this could cause the contact surface to shift, resulting in a rumbling noise. If it's newly replaced brake pads, a slight rustling sound in the first couple of days is actually quite normal because the friction material is still in the break-in period. But if you encounter a sharp, metal-tearing sound, don’t hesitate—get it checked immediately for any cracks in the brake discs. Safety is not something to take lightly.
