What Causes the Rattling Noise in Hill Descent Control Braking?
2 Answers
The causes of abnormal brake noises in cars are as follows: 1. Use of low-quality or overly hard brake pads: If low-quality or overly hard brake pads are used, they will produce a squeaking noise when they rub against the brake disc during braking. Therefore, it is essential to use high-quality brake pads when replacing them. 2. Presence of sand or foreign objects between the brake pad and brake disc: While driving, it is inevitable to encounter complex road conditions. Due to the unique design of disc brakes, some sand or foreign objects may get between the brake pad and brake disc, causing abnormal noises during braking. 3. Severe wear of the brake disc: For new cars, a slight squeaking noise during braking is normal and will diminish with more driving. For older cars, the brake disc and brake pads may have rusted. In this case, removing them and sanding off the rust layer can help. Alternatively, if the brake pads are severely worn, they should be replaced. 4. Brake pad warning: There is no strict rule on how many kilometers brake pads should be replaced; they should be replaced when they become thin. Some brake pads have electronic warnings, while some lower-end cars use warning tabs. If the wear reaches the warning line, a squeaking alarm sound will be emitted, indicating the need for immediate replacement. 5. Incorrect installation of brake pads: If the brake pads are installed incorrectly or the model does not match, abnormal noises will occur. The brake pads should be reinstalled properly. Car owners should have brake pads installed at professional auto repair shops, especially those who have had them replaced at roadside stalls, as extra caution is needed.
I also experienced a rattling sound from the brakes when using hill descent control before. At first, I was scared and thought something was wrong with the car. Actually, this is mostly a normal phenomenon when the hill descent control system automatically manages the brakes. The system frequently applies the ABS anti-lock braking function to prevent skidding on steep slopes, causing brief friction or vibration between the brake pads and discs, which produces the rattling sound. This is especially more common on slippery roads. If the sound is light and occasional, there’s generally no need to worry. However, I noticed that the noise worsens when the brake pads are severely worn or there’s debris on the brake discs, so I promptly went for a thorough inspection. I recommend paying attention to the frequency of the sound while driving—if it becomes too frequent or is accompanied by weak braking, be sure to visit a repair shop. Don’t overlook this small detail.
