What Causes Abnormal Noises When Braking a Car?

[JaceLee]

The reasons for abnormal noises when braking a car include new car break-in, driving through water, fine particles in the brakes, excessive wear of the brake discs, and brake system malfunctions. New car break-in: During the break-in period of a new car, the break-in of the brake pads is a crucial step. It usually takes several hundred kilometers of driving before the brakes feel properly adjusted. Driving through water: After driving through water, the brakes may produce abnormal noises, mainly due to the lack of lubrication caused by driving through puddles on rainy days, leading to brake wear or rust from water exposure. Fine particles in the brakes: While driving, very small sand particles may get between the brake pads and discs, sometimes causing abnormal noises due to friction. This situation generally does not require repair, as the small particles will fall out during driving. Excessive wear of the brake discs: Excessive wear of the brake discs, making them too thin, can also produce abnormal noises. Missing or damaged screws securing the brake discs can also cause brake noise.

[LillianRose]

Squeaking when braking is a common complaint I often hear from friends. The most frequent cause is worn brake pads. Manufacturers usually embed a small metal piece in the pads as a warning indicator—when the pads wear down to this point, it produces a sharp sound to alert you it's time for replacement. Another common issue is rust on the edges of the brake rotors. After washing the car or parking overnight in the rain, you might hear a clunking sound during the first few brakes the next morning, but this usually disappears after a few applications as the rust wears off. If the metallic grinding noise persists, it's best to check the brake pad thickness as soon as possible to avoid damaging the rotors, which would be more costly to repair.

[PeterFitz]

Brake noise issues need to be analyzed case by case. Last time I encountered this problem was when replacing brake pads. New brake pads may have surface coatings or poor initial contact with the rotors, causing squeaking sounds during the first few days of use - this usually disappears after driving about a hundred kilometers. If an older vehicle with original brake pads starts making noise, it's likely due to small stones or debris stuck between the pads and rotors, which should be promptly removed to prevent rotor damage. Also, pay attention to whether the brake caliper pistons retract properly - insufficient lubrication of guide pins can cause incomplete pad retraction, leading to dragging and noise. During regular maintenance, remember to ask the technician to apply special grease to the guide pins.

[EstherRose]

Brake noise while driving can indeed be annoying, especially in residential areas where it might disturb others. I've noticed that differences in brake pad materials can also lead to varying sounds. For instance, brake pads with higher metal content tend to squeak more at low temperatures. It's common to hear a creaking sound when lightly pressing the brakes during a cold morning start, but the noise usually disappears once the car warms up. Additionally, improper matching of aftermarket brake pads can more easily cause resonance and abnormal noises. It's advisable to first check the remaining thickness of the brake pads – if it's below 3mm, they should be replaced. If the noise persists after installing new brake pads, trying a few hard stops from 60 mph can help promote bedding-in.