What Causes Abnormal Noise When Starting the Car and Braking?
2 Answers
The reasons for abnormal noise when starting the car and braking are: 1. Brake run-in; 2. Normal activation of the ABS system; 3. Metal hard spots on the brake pads; 4. Severe wear of the brake disc; 5. Improper installation of the brake pads; 6. Sharp noise when braking in reverse; 7. Small stones or a water film between the brake disc and pads; 8. Foreign objects in the braking system; 9. Severe wear of the brake pads. The function of the brake is to reduce speed or stop the vehicle. Its working principle is: by using the friction between the brake pads and the brake drum, as well as between the tires and the ground, the kinetic energy of the moving vehicle is converted into heat energy after friction, thereby slowing down or stopping the car.
My experience tells me that when there is abnormal noise from the brakes during car startup, it is mainly due to rust or dust accumulation on the brake discs or pads. Especially after rainy days, if the car is parked for a while, an oxidation layer forms on the surface of the brake discs, causing a squeaking sound when you first apply the brakes, which can sound quite alarming. This situation is most common in humid weather, and if the noise disappears after driving for a short while, there’s no need to worry. Another possibility is that the brake pads are worn too thin, causing the metal backing to grind against the brake disc, producing a sharp noise. Over time, this can lead to deformation of the disc and pads. I’ve encountered this a few times while driving. First, check the remaining thickness of the brake pads and try cleaning off the rust or dust with compressed air. If the problem persists, don’t delay—take it to a repair shop immediately to check if the calipers are sticking, to avoid serious safety risks. These minor issues may seem simple, but ignoring them could lead to brake failure, especially during high-speed driving. Regularly washing your car to keep the brake system clean can help reduce this risk.