1. Quality problem of the new brake pad
Brake pads come from many sources, such as original parts, OEM parts, brand parts, sub-factory parts and so on, and there will even be some fake products. Different quality brake pad in the workmanship and materials are not the same, they will lead to a certain degree of abnormal noise.
If the mold itself is not good enough to make the brake pad, coupled with the manufacturer's control of the size and shape is not in place in the production process, this kind of brake pad once assembled to the car will be mismatched, resulting in local stress concentration of the brake pad or gap gap, in the brake process will naturally make noise. If there is a problem with the material of the brake pad, such as local hard spots or impurities, it will also make a shrill noise when rubbing against the brake disc.
2. There is no chamfer before the new brake pad is assembled
Because the original brake disc and brake pad after tens of thousands of kilometers of wear, so the brake disc will be worn with a gap in the width of the old brake pad. When replacing a new brake pad, its width does not match the brake pad 100%, so it is easy to squeeze against the brake disc at the corner, resulting in a squeak.
The solution to this problem is simply to use a file to chamfer around the edges of a new brake pad.
3. The clamping spring was not replaced at the same time
Brake pad are used to tighten the spring, different types of spring structure and number are different. Old brake pads have been used for a long time, so the fastening force is reduced, if not replaced at the same time or not installed will cause the brake pad in the calipers slightly wobble. In this way, in the powerful braking force, even if the calipers have a trace of the movement will also send out a "clatter clatter".
Now the vast majority of brake pad manufacturers will be equipped with a new spring in the packaging, but some repair shop because of the small union neglect to replace, the owner had better take the initiative to remind.
4. No muffler
The silencer's job is to create a layer of heat-resistant, elastic grease between the back of the brake pad and the calipers, thereby eliminating the vibrations that pass to the brake pad during braking, thereby eliminating noise. The original factory brake pad is with machine paint on the muffler grease, so in the replacement of the need for manual repainting. The muffler itself isn't worth much, but some of the rougher mechanics of the shop will skip the process, resulting in noise.
In addition, more exaggerated is some of the experience of the small workers although coated with muffler grease, but painted on the front of the brake pad (with the brake disc contact surface), the result of their friction coefficient drop, brake performance deterioration, and thus produce safety risks. Therefore the owner had better pay attention to the operation process of small work, nip in the bud.
5. There are sundries between brake disc and brake pad
When replacing the brake pad, if there is a hard impurity between the brake pad and brake disc, can cause noise because of the high intensity of the friction between the two. This is also the car in the process of most owners most often encountered problems. Therefore, when changing brake pad, must remind small workers to ensure that the brake pad and brake disc surface of the clean, the best can use non-lipid metal cleaning agent to clean one side, and then with air gun clean, so as to avoid impurities in disorder.
In summary, the brake pad replacement process or very exquisite, whether the process is not rigorous or material is not good, it is easy to produce abnormal sound. As an ordinary car owner, it is good for us to know some car knowledge in advance.