What is the reason for the abnormal noise of the brake disc

        Brake disc abnormal noise is one of the common problems in the use of automobiles, usually manifested as piercing metal friction sound, sharp whistling sound or other abnormal noise when braking. This kind of abnormal noise not only affects the driving experience, but may also indicate potential problems with the braking system that need to be checked and repaired in a timely manner. The following are common causes and detailed analysis of brake disc abnormal noise:
        1. Excessive wear of brake pads. Brake pads are components in the brake system that come into direct contact with the brake disc, and their surfaces are typically made of friction materials such as ceramics, metals, or organic materials. When the brake pads wear out to a certain extent, the friction material is almost exhausted, and the metal backing plate will directly contact the brake disc, causing metal friction sound. This situation is usually accompanied by a decrease in braking performance and requires immediate replacement of brake pads.
        Solution: Regularly check the wear of brake pads, and replace them promptly when the thickness approaches or falls below the minimum value specified by the manufacturer.
        2. The surface of the brake disc is uneven. During long-term use, the brake disc may experience scratches, grooves, or deformation due to high temperatures, uneven friction, or external forces. These uneven surfaces can cause vibrations when the brake pads come into contact with the brake discs, resulting in abnormal noises.
        Solution: If there are slight scratches on the surface of the brake disc, it can be repaired through a "disc" (i.e. turning and polishing the brake disc); If the deformation is severe or the thickness is insufficient, the brake disc needs to be replaced.
        3. Foreign objects may enter between the brake pads and brake discs during driving, such as sand, stones, dust, or other foreign objects. These foreign objects will be squeezed during braking, causing a piercing noise. In addition, foreign objects may also scratch the surface of the brake disc, further exacerbating the problem.
        Solution: Clean the brake system and remove foreign objects. If the brake disc has been scratched, it is necessary to determine whether to repair or replace it based on the degree of damage.
        4. The material of brake pads directly affects their friction performance and noise performance. Some low-quality or inferior brake pads may contain excessive metal components, resulting in sharp whistling sounds when rubbing against the brake disc. In addition, the mismatch between the hardness of brake pads and brake discs can also cause abnormal noise.
        Solution: Choose brake pads with reliable quality that match the brake disc, and avoid using inferior products.
        5. The brake system lacks lubrication. Certain components in the brake system, such as brake pads, calipers, and guide pins, require regular lubrication to ensure their proper functioning. If there is a lack of lubrication, the brake pads may not return smoothly, resulting in continuous friction with the brake disc and producing abnormal noise.
        Solution: Regularly inspect the brake system and clean and lubricate the components that require lubrication.
        6. Improper installation of brake pads. If the brake pads are not installed according to the specifications (such as not properly fixed or not installed with sound-absorbing pads), it may cause poor contact between the brake pads and the brake disc, resulting in abnormal noise. In addition, failure to clean the dust or grease on the surface of brake pads and brake discs during installation may also cause problems.
        Solution: Ensure that the brake pads are installed properly, and use sound-absorbing pads or sound-absorbing paste if necessary.

        7. Overheating of brake discs or brake pads: In situations of frequent braking or intense driving, brake discs and brake pads may deform or develop thermal cracks due to overheating, leading to abnormal noise. In addition, high temperatures may also harden the surface of brake pads, further exacerbating noise.
        Solution: Avoid prolonged and frequent braking, especially on downhill roads. If the brake system overheats, stop and cool down before continuing to drive.
        8. Poor brake pad return. Brake pads should quickly return to their original position after braking to avoid continuous contact with the brake disc. If the return is poor (such as stuck caliper piston or corroded guide pin), the brake pads may rub slightly against the brake disc, causing abnormal noise.
        Solution: Check the working condition of the caliper piston and guide pin, and clean, lubricate or replace them if necessary.
        9. Environmental factors: In humid or rainy environments, a thin layer of rust may form on the surface of the brake disc, causing abnormal noise during braking. This kind of abnormal noise is usually temporary and gradually disappears with the friction of the brake pads.
        Solution: No special treatment is required, but after driving in a humid environment, it is recommended to step on the brakes a few times to remove rust.
        10. Brake system design or quality issues. Some car models may have design defects or quality issues in their brake systems, leading to frequent abnormal noises. For example, poor material of brake discs, poor matching between brake pads and brake discs, etc.
        Solution: If you suspect a design or quality issue, it is recommended to contact the manufacturer or a professional repair organization for inspection and handling.
        11. Brake pads or brake discs that have not been worn in. Newly replaced brake pads or brake discs need to be worn in for a period of time to reach their optimal working condition. During the running in period, abnormal noise may occur due to uneven contact surfaces.
        Solution: Follow the manufacturer's recommendations for running in, and the abnormal noise will usually gradually disappear within a few hundred kilometers.
        12.If the vehicle is parked for a long time, the surface of the brake disc may rust due to moisture. Rust can cause abnormal noise when brake pads come into contact with brake discs.
        Solution: After a long period of parking, it is recommended to drive at low speed and lightly apply the brakes a few times to remove rust.
        There are various reasons for the abnormal noise of brake discs, which may be normal phenomena (such as new brake pads breaking in or humid environment), or signals of brake system problems (such as brake pad wear or brake disc deformation). To avoid safety hazards, it is recommended to promptly check the brake system after discovering abnormal noises and take corresponding solutions based on the specific reasons. In addition, regular maintenance and standardized driving habits can effectively reduce the occurrence of brake disc noise.