1. Quality problem of new brake pads
Brake pads come from many sources, such as original parts, OEM parts, brand parts, sub-parts and so on, and even some fake products. Brake pads of different quality are different in workmanship and materials, they can lead to abnormal noise to some extent.
If the production of the brake pad mold itself is not good enough, coupled with the manufacturers in the production process of the size and shape of the control is not in place, the brake pad once assembled on the car will appear poor matching, resulting in the local stress concentration or gap gap, in the process of braking natural noise. If there is a problem with the brake pad material, such as local hard spots or impurities, it will also give out a sharp squeal when rubbing the brake disc.
2. There is no chamfering before assembling the new brake pads
Because the original brake disc and brake pad after tens of thousands of kilometers of running in, so the brake disc will be worn out with the width of the old brake pad groove. When a new brake pad is replaced, its width does not match 100% of the brake pad, so it is easy to squeeze the brake pad at the corner, resulting in a squeal.
The solution to this problem is simple: use a file to chamfer the corners around the new brake pad. This can be easily avoided by rounding the right corners.
3. The card spring was not replaced at the same time
Brake pads are used for fastening the spring, the structure and number of different models of spring are not the same. Since the spring of the old brake pad has been used for a long time, the fastening force has decreased. If not replaced at the same time or not installed properly, the brake pad will be slightly shaken in the calipers. In this way, in the strong braking force, even if the calipers have a trace of channeling will also give out "clunk clunk" of the unusual sound.
Now the vast majority of brake brake manufacturers will be equipped with a new spring in the package, but some repair shop small labor union because of negligence forget to replace, the owner had better take the initiative to remind.
4. No muffler
Silencing lipids are used to create a layer of heat-resistant and resilient grease between the back of the brake pad and the calipers, eliminating the vibrations that are transmitted to the brake pad during braking, thus eliminating noise. The brake pads of the original factory are filled with silencer with machine daub, so manual redaub is required when replacing. Silencer grease itself is not valuable, but some of the more rough process of the auto repair shop will skip this step, so bring abnormal noise.
In addition, what is more exaggerated is that some inexperienced workers although coated with muffler grease, but painted on the front of the brake pad (the face in contact with the brake disc), resulting in their friction coefficient dropped, brake performance deteriorated sharply, resulting in safety hazards. Therefore, the owner of the car had better pay attention to the small operation process, nip in the bud.
5. There is debris between the brake disc and brake pad
When replacing the brake pad, if there is a hard impurity between the brake pad and the brake disc, it will produce noise because of the high friction between the two. This is also the most common problem encountered by most car owners in the process. When changing brake pad accordingly, must remind small work to ensure the clean of brake pad and brake disc surface, had better use the metal that is not fat to clean agent first one side, blow clean with air gun again, lest impurity enters disorderly.
To sum up, the brake pad replacement process or very exquisite, whether the process is not rigorous or material is not perfect, are easy to produce abnormal noise. It's good for us as average car owners to know a little about cars in advance.