Industry News

Uncover the Truth of Abnormal Brake Noise


1. Why does the brake pad make noise during the running in period?

After the new brake pad is installed, the contact surface is incomplete before running in, so the expected braking effect cannot be achieved.
After running in, the contact surface will be complete to achieve the best braking effect.
Running in period plan
After installing new brake pads, step on the brake pedal several times before starting to eliminate the gap during installation
The best braking effect can be seen after 200 km of running in, and continuous braking and emergency braking shall be avoided as far as possible.
2. There are foreign matters on the brake pad

When the brake disc meets water at high temperature during braking, the brake disc is instantly "quenched" to form hard spots on the surface, which reduces its toughness. During braking, the quenched metal of the brake disc enters the brake pad, causing abnormal noise.
Although the quenched metal entering the brake pad will not affect the braking effect, it will cause abnormal wear and noise of the brake disc.

Check and clean or replace the brake disc, polish or replace the brake pad.

3.Poor return of brake caliper and eccentric wear

The caliper is rusted or stuck, resulting in insufficient lubrication of the guide pin and poor return, resulting in incomplete contact between the brake pad and the brake disc, eccentric wear and abnormal noise, affecting the braking effect, thus reducing the service life of the brake pad.


Check the return of the brake wheel cylinder and guide pin; Check the translation of the brake pad in the bracket; Perform in-depth maintenance of the brake system and replace the brake pads.

4. The brake disc is severely worn

The reason is that the brake disc is excessively worn and there are steps on the edge, which causes the edge wear of the friction material of the brake pad to be more serious than the middle part, resulting in high-frequency abnormal noise, brake pedal shaking, and abnormal wear of the friction material when the brake is stepped on.


Check whether the brake pad matches the brake disc; Check the friction area difference between the brake pad and the brake disc;
Check or replace the brake disc.

5. Excessive high temperature braking

1. The brake caliper does not return to its original position. If the brake caliper does not return to its original position for a long time, the temperature of the brake pads will be too high, causing erosion and deterioration of the friction materials, or failure of the adhesive;
2. Slag falling or falling off due to long-time braking. This situation is mainly caused by long-time downhill. In mountainous areas, the road is long due to steep slopes. Experienced drivers use intermittent braking to go downhill, but novices tend to brake continuously for a long time, which is easy to cause ablation, slag and peeling of the film;

Check the return of the brake caliper and carry out in-depth maintenance of the brake system; Check the brake disc and replace it as appropriate; Replace the brake pads;

6. Abnormal sound of cold brake

In seasonal wet weather, it is easy to have low-frequency and harsh abnormal braking noise when the car is cold. The main reason is that when the brake disc is in a wet environment, it is easy to form oxide layer on the surface, which will cause the brake disc to brake pad contact surface to change during braking, causing abnormal noise


After several times of braking, the oxidized part of the brake disc surface is smoothed, so that the brake pads closely fit with the contact surface of the brake disc, and the abnormal noise disappears.

7. Brake pad material

We know that most brake pads are made of semi metal materials. That is to say, there are a lot of metal fibers in the brake pads. If the manufacturing process is not good, it is easy to mix large metal particles or the brake pads are too hard, so it is easy to make abnormal noises


Do not use low-quality brake pads, please choose the brake pads produced by regular manufacturers.

8. The friction coefficient is too high

The friction coefficient is too high, making the brake pads look like cutting the brake disc; The stiffness of the brake pad is just close to that of the brake disc, which is easy to generate resonance, and the sound is generated by vibration;


Replace the brake pads and brake discs that meet the rated coefficient.

9. The brake pads are completely worn

If this is a squeal, first check that the brake pads are almost used up (the alarm pads sound)
The friction between the metal of the brake pad and the brake disc is serious, and the brake disc is damaged.

Check the wear of the brake pads and brake discs, replace the brake pads, and replace the brake discs as appropriate