Why does the brake disc make a noise when starting in rainy days?
4 Answers
There are many reasons why the brake disc makes a noise when starting in rainy days, such as severe wear of the brake pads, excessive wear of the brake drum, etc. Severe wear of the brake pads: If there is abnormal brake noise during low-speed driving, it is likely due to severe wear of the brake pads. The warning piece will emit a sharp abnormal noise to prompt replacement. Alternatively, excessive wear of the brake disc or brake drum, making them too thin, may also produce abnormal noise. It could also be that the brake pads have just been replaced and do not fit properly with the contact surface of the brake disc or drum, resulting in point or line contact and causing abnormal noise. Brake pads not replaced for a long time: The replacement cycle of brake pads is not fixed and depends on the vehicle's driving conditions, the frequency and intensity of the driver stepping on the brake pedal.
As an experienced driver, I often encounter a brief squeaking sound from the brake discs when starting the car in rainy conditions. After parking, rainwater splashes onto the discs, causing moisture to form a thin layer of rust on the metal surface. When you start the vehicle and apply the brakes, the friction between the brake pads and discs removes this rust layer, resulting in a short-lived noise that usually disappears after one squeak. This isn't a major issue and typically goes away after a few brake applications or a short drive. However, if the sound is consistently harsh or occurs multiple times in succession, it's advisable to check for excessive brake pad wear or debris lodged in the system. Rainy conditions already reduce braking efficiency, so consider this sound as a gentle reminder to maintain safe following distances and avoid sudden acceleration. Parking in dry areas when possible can help minimize this occurrence.
I often study automotive mechanical principles. The squeaking sound from brake discs when starting in rainy weather is mainly caused by surface rust due to moisture. The humidity from rainwater stays on the disc surface, forming rust after oxidation. When the vehicle starts, the brake friction removes this rust, creating noise. This phenomenon is quite common and doesn't affect braking performance, usually disappearing within seconds. If the sound persists, it might indicate uneven disc surfaces or accumulated dust increasing friction. Rainwater effects also include reduced braking force, so it's advisable to start gently and lightly apply brakes to warm them up. For long-term exposure to humid environments, regularly inspect the brake system for cleanliness, and using anti-rust spray can prevent rust issues and extend component lifespan.
To reduce that annoying brake noise when starting in rainy weather, I suggest making some small daily adjustments. Try to park indoors to avoid getting wet; before driving, gently press the brakes a few times at low speed to remove moisture and rust; make it a habit to clean the brake parts after wet weather to remove scale; maintain low speed during the initial driving phase to allow the brakes to warm up smoothly. This not only reduces noise but also protects the brake pads. Occasional noise once or twice is normal and will disappear once the water and rust are cleared. Avoid frequent hard braking in rainy weather to prevent additional wear and more serious abnormal noises.
