What are the causes of brake noise at low speeds?
3 Answers
Causes of brake noise at low speeds: 1. Running-in of a new car, where the brake pads' running-in is an important part. Usually, after driving a few hundred kilometers, the brakes will feel more comfortable; 2. Brake noise may occur after the car has driven through water, mainly due to wear caused by the lack of lubrication from driving through puddles on rainy days, or possibly due to rust from water exposure; 3. Very fine sand particles may get between the pads and discs while driving, sometimes causing noise due to friction. In most cases, this does not require repair; 4. Excessive wear of the brake discs or brake drums, which may become too thin and cause noise; 5. Missing or damaged fixing screws of the brake discs can also cause brake noise; 6. Malfunction of the brake system, which requires inspection and repair.
There are various reasons for low-speed brake squealing. From my years of driving experience, the most common cause is excessively worn brake pads, where the metal backing plate directly grinds against the brake disc, producing that harsh screeching sound. This issue particularly occurs after several years of vehicle use when the pads become thin. Secondly, rusted brake discs are also quite common, especially when starting the car after parking during rainy seasons or in humid weather. Slight rust on the disc surface causes uneven friction, resulting in a few clunking sounds that usually disappear after a few brake applications. Additionally, contamination in the brake system, such as accumulated dust, grease, or small stones stuck between the pads and disc, can cause abnormal friction and noise. Moreover, loose brake calipers or dry pins can also generate unusual sounds at low speeds. If these issues are not addressed promptly, they not only create annoying noise but also wear down the brake system and increase driving risks. Therefore, I recommend getting a check-up and repair as soon as any abnormal sounds are heard to prevent more serious problems.
In the cases I've encountered, excessive brake pad wear is the top culprit for squealing brakes at low speeds. When the pads are completely worn out, metal-to-metal contact creates a harsh, unpleasant noise. Another common issue is scratched, corroded, or dirty brake rotor surfaces, causing uneven contact with the friction material and resulting in squeaks—especially more frequent during humid seasons. Hardware problems like loose caliper assembly or improperly secured shims can also cause wobbling and noise during braking. Additionally, if you're driving an older vehicle, excessive residual lubricants or dust buildup in the system may trigger irregular friction noises. Environmental factors should also be considered; material contraction/expansion in cold temperatures or high humidity can make noises more noticeable. Don't delay when noticing such issues—check brake thickness and system cleanliness, and visit a professional repair shop if needed to ensure driving safety.
