What are the reasons for brake noise?
4 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.
When my best friend's Fit first had brake noise, it scared her to death. Later, we found out it was just rust on the brake discs after washing the car. Especially during the rainy season, leaving the car parked outside for a few days causes surface rust on the discs, and the friction with the brake pads makes a squeaky noise. Driving a few kilometers to wear off the rust usually quiets it down—much more reliable than being tricked by repair shops into replacing the entire set of parts. Also, in winter when temperatures drop, the metal particles in the brake pads harden and are more prone to squealing. This is a common issue when starting the car in the morning. If you hear a clicking noise when reversing, be cautious—it could be due to stuck guide pins causing poor brake pad retraction, which can lead to uneven wear over time. We female drivers are most sensitive to these strange noises, but don’t rush to be taken for a fool. First, ask the mechanic to check the caliper’s condition with an endoscope—that’s the most practical approach.
The year I first started driving, the screeching sound of brakes always startled me. Actually, a brief squeak during cold starts is mostly normal, especially with cast iron brake discs that expand and contract with temperature changes, creating slight gaps. However, if the noise persists while braking and is accompanied by vibrations, three key points need inspection: check if the brake discs have deep grooves; feel the brake pads for hard spots; and examine whether the dust shield is deformed and rubbing against the rotor. My driving instructor taught me a practical trick—apply moderate braking force ten times in a row. If the noise disappears, it’s likely due to resonance from grooves on the brake discs. Modified brake calipers are more prone to noise and require copper-based grease on the bracket contact surfaces. Remember, as long as there’s no abnormal sound when braking at speed, there’s usually no need to panic.
