What are the causes of brake pad noise?
3 Answers
Brake pad noise can be caused by: 1. Lack of disc surfacing leading to brake pad noise; 2. Defects in the braking system causing only partial contact between the brake pad and disc, resulting in noise; 3. Unauthorized manual grinding or modification of brake pads, reducing the contact area between the pad and disc and causing noise; 4. Frequent emergency braking, wheel lock-up, or faulty brake calipers causing prolonged overheating of the brakes, leading to brittle friction material or even cracking, which results in noise. Brake pads are friction materials fixed to the rotating brake drum or disc of a wheel. The friction linings and blocks within them withstand external pressure to generate friction, thereby achieving vehicle deceleration.
As a seasoned auto mechanic with years of experience, I've encountered numerous brake pad noise issues. The most common cause is dust or small stones stuck on the brake pads, which create screeching sounds when rubbing against the rotors during braking. Another reason is uneven wear of brake pads, such as rough edges or uneven surfaces, leading to irregular contact. Additionally, rusted brake rotors—especially after rainy or humid conditions—can also cause noises. Improper installation is another factor, like misaligned pads and rotors or loose screws. I always remind car owners to conduct regular inspections, preferably quarterly checks at professional shops for pad thickness and rotor surface conditions, to prevent overlooked issues that may reduce braking performance. Long-term neglect of such noises may accelerate damage to other components and increase repair costs.
I once experienced brake squealing while driving, which sounded like metal grinding. Later, I went for an inspection, and the technician said it might be due to excessive wear on the brake pads. When they become too thin, they can make poor contact with the rotors. Alternatively, low-quality pad materials that can't withstand high temperatures may deform and produce noise after frequent braking. Environmental factors also play a role, such as rust forming on the rotors after driving through water in rainy conditions, causing noise during the next brake application. I tried cleaning the surface of the brake pads myself to remove debris, but it didn't help much. In the end, replacing the pads solved the issue. I recommend that car owners not delay when they hear such sounds and get them checked early. Otherwise, unstable braking on the road can be very dangerous. I make it a habit to visually inspect my brake pads when I wash my car weekly—it's both convenient and ensures safety.
