What Causes the Friction Sound in Disc Brakes?
3 Answers
The causes of friction sound in disc brakes include the brake pads being in the break-in period, the presence of metal particles in the brake pads, excessive wear of the brake disc and brake pads, and deformation of the brake disc. Solutions for friction sound in disc brakes: Remove the brake pads and sand off the rust layer, or replace the brake pads if they are severely worn; have the work done at a professional auto repair shop. For safety, timely maintenance is essential as the braking system directly affects the vehicle's driving safety and is a high-wear component. Regular maintenance checks and part replacements are recommended, with brake pads typically replaced every 60,000 to 80,000 kilometers and brake discs every 100,000 to 120,000 kilometers. The function of brakes is to reduce speed or bring the vehicle to a stop. The working principle involves converting the kinetic energy of the moving vehicle into heat energy through friction between the brake pads and brake drum, as well as between the tires and the ground, thereby slowing or stopping the vehicle. Disc brakes consist of a brake disc connected to the wheel and a brake caliper at the edge of the disc. During braking, high-pressure brake fluid pushes the brake pads to clamp the brake disc, creating a braking effect. Disc brakes are sometimes called rotor brakes and come in two types: standard disc brakes and ventilated disc brakes.
My car's disc brakes started making a grinding noise recently, and upon investigation, I found several possible causes. When the brake pads wear too thin, the metal part contacts the rotor, producing a sharp screeching sound, especially noticeable during light braking. If the brake rotor surface is uneven or rusty, particularly after rain when moisture is present, the rust friction can also cause noise. Sometimes, small stones or dirt get stuck between the pad and rotor, leading to intermittent noises. I’ve also encountered issues with stuck or slow-retracting brake caliper pistons—if the piston doesn’t retract promptly, the pad keeps rubbing against the rotor, causing noise. Loose screws or improper installation can create vibration sounds as well. The key takeaway: ignoring these issues may lead to severe rotor wear or even brake failure, increasing the risk of accidents. I recommend monthly self-checks: inspect whether the pad thickness is below 3mm and gently feel the rotor surface for smoothness. If any abnormal noise occurs, visit a professional shop for inspection and maintenance as soon as possible to ensure driving safety. Regular wheel hub cleaning and timely pad replacement extend service life—good habits bring peace of mind.
I recently experienced a squeaking issue with my disc brakes. Initially, I thought it was normal noise during the break-in period of a new car. After it happened several times, I checked the brake pads and found they had worn beyond the limit, causing metal-to-disc friction noise. There were also slight scratches on the disc surface, possibly caused by sand and dust scraping during driving. The mechanic explained: foreign object intrusion is common after rain or driving on dirt roads; over-tightened or loose installation screws can also cause vibration noise. I learned to pay attention to sound changes in daily use: low-speed braking noise is often caused by foreign objects or rust; high-pitched squealing usually indicates severe pad wear. From a safety perspective, ignoring noise can reduce braking performance and make skidding more dangerous in rainy conditions. Since then, I’ve started DIY prevention: rinsing the wheels during car washes to reduce debris and checking pad condition every six months. Spending a little time on maintenance helps avoid costly disc and pad replacements. Developing good habits saves both hassle and money.
