What Causes the Abnormal Noise When Releasing the Brake During Car Start-Up?
2 Answers
Car start-up abnormal noise when releasing the brake can be caused by the following reasons: 1. The brake pads and brake discs are brand new and have not undergone a break-in period, leading to unusual noises. 2. Foreign objects between the brake pads and brake discs causing abnormal braking noise: While driving, small particles like sand may enter between the brake pads and brake discs, sometimes creating noise due to friction. 3. Low temperatures causing abnormal braking noise: A low-frequency noise occurs when braking during a cold start. Due to the low temperature, the rubber components of the chassis suspension become stiff, and some may work together with the frame, causing vibrations in the brake calipers or suspension system, resulting in low-frequency noise. 4. Loose or aged suspension and chassis components leading to abnormal braking noise: Missing or damaged brake disc fixing screws can also cause abnormal braking noise. Loose or aged components such as shock absorber fixing screws, stabilizer bar rubber bushings, and ball joints can cause abnormal braking noise while driving. 5. Brake disc corrosion causing abnormal braking noise: The vehicle's brake discs and brake pads may corrode due to water exposure or prolonged parking, especially after prolonged use of the handbrake, causing the brake discs and brake pads to stick together and produce noise during initial driving. In this case, pressing the brakes a few more times will make the noise disappear after driving for a while. 6. Severely worn brake pads or brake discs causing abnormal braking noise: Brake pads usually have warning indicators. When the brake pads wear to their limit, the warning indicators will rub against the brake discs, producing abnormal noise. When the brake discs wear, due to surface contamination, uneven material density, excessive working temperature, or mismatched installation torque, abnormal noise may occur.
After working in the auto repair industry for a long time, I've encountered many cases of abnormal noises when releasing the brakes during vehicle startup. The most common causes are rust or dirt buildup on the brake disc surface, especially after parking in humid weather when metal components tend to accumulate condensation, resulting in squeaking sounds from disc-pad friction. Additionally, uneven wear or excessively thin brake pads can produce similar noises, or issues like improperly retracted brake calipers or stuck guide pins causing friction resistance. I always advise car owners to regularly inspect their braking systems - checking for disc scoring during pad replacement, or performing several brake applications after car washes to remove rust through heat cycling. Safe driving should never be taken lightly. If abnormal noises persist or intensify, promptly visit a professional repair shop to prevent potential accidents caused by reduced braking performance.
