What are the factors that cause abnormal noise when braking at low speeds?

[LeJuliette]

There are two possible factors that may cause abnormal noise when braking at low speeds: 1. The brake pads have worn to their limit, causing the small metal plate to come into contact with the brake disc. Normally, there is a certain distance between this small metal plate and the brake disc, preventing friction. However, when the brake pads wear down to the limit, the small metal plate contacts the brake disc, and the friction between metal surfaces produces a squeaking sound, alerting the driver to replace the brake pads immediately. Therefore, if there is noise, promptly check the brake pads. 2. The brake pads contain relatively large metal particles, and the noise generated from friction with the brake disc is also due to metal-to-metal contact. This issue has occurred in many vehicles. To eliminate the abnormal noise, the brake pads must be removed and polished. Using sandpaper to grind off a layer of the brake pads will remove the exposed metal particles, preventing further noise.

[LaWalter]

A few days ago, I kept hearing squeaking sounds when braking at low speeds while driving, which was quite annoying. It might be due to uneven wear on the brake pads, especially after several years of use—some areas of the pads may be thinner or thicker, causing noise when rubbing. Alternatively, there could be slight rust on the brake disc surface, which often happens after driving in the rain and leaving the car parked overnight, leading to noise the next morning. Newly replaced brake pads also often produce noise during the break-in period, which usually disappears after a few hundred kilometers. However, for older cars, it’s also worth checking if the brake calipers lack lubrication, causing the pads to stick and become less flexible. Long-term neglect could affect braking performance, so for safety, I recommend having a technician check the thickness of the pads and discs during regular maintenance and avoiding sudden braking to reduce wear.

[MaliaMarie]

I often help people with car issues, and low-speed brake squealing is usually a minor problem with the braking system. The most common causes are poor-quality or fast-wearing brake pads, which can squeak when small stones or dust get embedded. Uneven brake disc surfaces or hot spots are also culprits, especially when rust is more noticeable in humid conditions. You can check it yourself: After parking, feel the brake discs—if they're overly hot, it might be a caliper issue. For new cars, the noise typically fades after a week or two of breaking in, but older vehicles should be checked at a shop to see if the discs need resurfacing or new pads. Remember to regularly clean the brake area to prevent dirt buildup.

[JeremiahMarie]

I just learned to drive not long ago, and there's always a strange noise when braking at low speeds, somewhat like a squeaking sound of grinding, which makes me a bit uneasy. I asked my friends, and they said it might be due to newly replaced brake pads or rust on the discs caused by humid weather, and it would get better after driving for a few days after rain. Some also said new pads would quiet down after a break-in period. However, safety is important. If the noise is loud or frequent, I'm considering going to a repair shop to have the pads and discs checked and adjusted if necessary, to prevent small issues from turning into big ones.