What Causes Abnormal Noises During Starting and Braking?
2 Answers
The causes of abnormal noises during starting and braking are as follows: 1. The speed of starting and braking is too slow: This is a common issue for many automatic transmission car owners. When the brake pedal is slowly released, the engine already has sufficient power to drive the car, but the brakes are not fully released. As a result, the moving wheels are held back by the braking system, naturally producing abnormal noises, which is a normal phenomenon. 2. The break-in period of a new car: Generally, new cars have been in stock for a relatively long time, and the brake discs are very prone to rust. Therefore, applying the brakes during the break-in period can produce abnormal noises. However, after a break-in period of more than 200 kilometers, the noise usually becomes less noticeable, and braking becomes more powerful. 3. When replacing the friction pads, no noise-reducing paste was applied or the pads were not chamfered: This prevents the new brake discs from properly breaking in with the friction pads, leading to abnormal noises. 4. Hard foreign objects entering the gap between the brake pads and brake discs: In this case, the braking system may experience jamming during operation. When foreign objects get into the gap of the brake discs, abnormal braking noises occur.
I've been driving for several years and found that abnormal noises during starting and braking are quite common. Most of the time, it's caused by worn or aged brake pads, especially noticeable in cold or humid weather. The metal-on-metal friction sounds like scraping, and it might be louder right after starting because the brake disc surface could be rusty or have dust buildup. Another reason could be a faulty suspension system, like loose springs or failing shock absorbers, causing squeaking sounds when the car shakes, particularly noticeable at the moment of starting. If the wheel bearings lack lubrication or are damaged, they can also produce noise at low speeds. There's also the possibility of small stones or debris getting into the brake system, causing jamming. Personally, I think once you hear such noises, you should check the brake pad thickness—if they're too thin, replace them immediately. During regular car washes, pay attention to cleaning the dirt around the wheel hubs to prevent dust accumulation. Long-term neglect could lead to brake failure, affecting driving safety, so I recommend finding a reliable repair shop for a thorough diagnosis.
