What Causes Abnormal Noises in Car Brakes?
4 Answers
Abnormal noises in car brakes can be caused by the following reasons: 1. Brake bedding-in: New cars or recently replaced brake discs and pads have a break-in period, during which some noise is inevitable. This noise, which can include vibration friction or sharp squealing sounds, usually disappears after driving a few hundred kilometers. 2. Normal ABS system activation: During hard braking, the brake pedal may produce a continuous "thudding" sound, sometimes accompanied by pedal pulsation. This indicates the ABS system is functioning normally. In such cases, simply press the brake pedal firmly (applicable only to vehicles equipped with ABS). 3. Metal hard spots in brake pads: Small metal particles in the brake pads can cause sharp, piercing noises when braking lightly. This issue can be resolved by braking hard several times, removing and resurfacing the brake pads, or replacing them with higher-quality ones. 4. Severe brake disc wear: Worn brake discs develop deep grooves around their circumference, causing noise when the brake pads rub against the groove edges. If the grooves are not too deep, resurfacing the edges of the brake pads can help avoid the friction. However, if the grooves are deep, replacing the brake disc is recommended. 5. Improper brake pad installation: Reinstalling the brake pads and applying grease or specialized lubricant to the connection points between the pads and calipers can solve the issue. Noise may also occur if the brake pads are installed backward, which can be fixed by reinstalling them correctly. 6. Small stones or water film between brake discs and pads: This can happen after driving on gravel roads, during dusty weather, or after washing the car. The noise can usually be eliminated by braking several times or removing the stones. 7. Foreign objects in the brake system: Dusty or sandy conditions can cause particles to enter between the discs and pads, resulting in hissing noises during braking.
I've been driving for almost ten years and have encountered the issue of abnormal noises when braking many times. Usually, it's caused by excessive wear of the brake pads leading to metal grinding against the brake disc, which sounds like a sharp scraping noise. Especially right after replacing new brake pads, if they haven't been properly broken in, they can also produce a humming sound. On rainy days when it's humid, the brake discs rust, making the first brake application particularly loud, but the noise disappears after driving a short distance. Once in winter, the noise was even worse when the car was cold because the components were frozen. I've learned that such noises shouldn't be ignored, as they might indicate a problem with the braking system, such as a warped disc or debris stuck in it. It's best to first check the thickness of the brake pads yourself—if they're too thin, replace them. Or, go directly to a professional auto repair shop for a brake inspection. Addressing the issue early can save a lot of money and ensure driving safety.
As someone who regularly maintains my car, I think there are quite a few common causes for brake noise. New brake pads might squeak when first installed, but the noise usually goes away after a few days of driving. However, if the noise persists, it's worth checking whether the pads are made of inferior materials or were improperly installed. Dirty or scratched brake rotors can also cause noise, especially after driving on dusty roads. I make it a habit to clean the brake pads when washing my car every week to prevent debris buildup. Large temperature changes can also cause abnormal noises due to thermal expansion and contraction. If you hear any unusual sounds, don't delay—most of the time, it means the brake pads are wearing out. Quickly measure their thickness, and if it's below the safe limit, replace them immediately. The maintenance manual recommends checking the brakes every quarter. Developing this habit can help reduce such issues and avoid last-minute repairs that could affect driving confidence.
Recently, my car makes a creaking sound whenever I brake. After checking, I found there are only a few possible reasons. The brake pads are worn out, exposing the metal backing plate; or the brake disc surface is uneven or dirty; it's normal for new cars to make noise during the first few days of the break-in period. Some noises occur due to rust after getting wet, or when braking for the first time in cold weather. Simple self-inspection can help: if the brake pad thickness is visually less than 3mm, replacement is needed; if there's noise, stop the car and check if there are small stones or metal debris stuck in the wheel hub. If any abnormalities are found, go to the repair shop promptly—don't risk driving, as brake failure could lead to an accident.
