When we drive, slowing down and braking is a very frequent action. Because it is related to driving safety, everyone attaches great importance to the performance of the vehicle braking system, and is also very sensitive to abnormal phenomena during braking.
Auto repair shops often encounter such descriptions: When you press the brake pedal while driving, you will feel the pedal shake. Is this jitter a malfunction? 1. Vibration caused by abnormal deformation of brake disc (drum) Let's first look at the brake pedal vibration caused by abnormal brake components. When the surface of the disc brake deforms and undulates, the pedal vibrates due to the undulations of the brake disc during braking. For vehicles with drum brakes, if the inside of the brake drum is not round, a similar sloshing phenomenon can occur. This brake pedal shake caused by component anomalies is related to wheel speed. The higher the wheel speed, the higher the frequency of pedal vibration when braking. In addition, if the brake drum is not round, the body will shake within a certain speed range due to poor dynamic balance during normal driving. Deformation of the brake disc (drum) is usually caused by thermal changes or poor component materials. For example, when the vehicle has just finished driving intensely and the temperature of the brake disc (drum) is very high, when the surface of the high-temperature brake disc (drum) becomes cold instantly, it is easy to cause the local extreme temperature drop of the metal parts, resulting in the brake disc (drum). ) The surface shrinks unevenly and fluctuates. In this case, it is recommended to replace the brake disc (drum).
2. Pedal vibration during emergency braking When the braking system is normal, the brake pedal will vibrate, such as the ABS anti-lock braking system works. When a vehicle is driving on the road, it is inevitable to encounter unexpected situations that require emergency braking. When the vehicle speed is high, the emergency braking is adopted, the ABS anti-lock braking system works, and the "high frequency point braking" is implemented to prevent the wheels from locking. Emergency braking activates the anti-lock braking function, giving the driver a high-frequency vibration of the brake pedal. This is completely normal and car owners need not worry.
3. Pedal jitter when braking on slippery roads When the vehicle is driving on wet roads such as rain or snow, the pedal is often felt when the brake is pressed. This is because the grip of the tires is significantly reduced and the wheels are more likely to lock up when braking. Anti-lock Braking System The anti-lock braking system will monitor the tendency of the wheels to lock up via wheel speed sensors. Anti-lock braking is activated when a risk of wheel locking is detected. Therefore, in rain and snow conditions, the anti-lock braking function will frequently intervene, causing the brake pedal to vibrate, which is also a normal phenomenon.