What is the reason for the abnormal noise of the brakes in the rain?

In rainy days, the fine sand brought up by the water adheres to the brake discs. In wet weather or when the temperature difference between day and night is large, the brake discs will rust after water or rain. It is equivalent to fine particles. The pads of cars have hard and soft The difference is that the hard one is more wear-resistant, but if there are small particles between the hard pad and the gray cast iron brake disc, there will be a sharp sound. It is good to wear off the small particles with a few brakes.

　　

If there is abnormal sound when the vehicle brakes, there are usually the following situations: one of the factors is that the new car itself will have a running-in period. The moving disc is very easy to rust and has rust spots, so if you step on the brakes during the running-in process of the vehicle, it will produce abnormal noise, but this situation usually occurs after more than 200 kilometers of running-in. improved and more powerful braking. The second reason is that the master worker did not apply sound-absorbing paste to the friction plate or did not chamfer the friction plate when replacing the new friction plate. A good break-in causes abnormal noise. The third reason is that when the vehicle passes through wading roads or muddy roads, hard foreign objects enter the gap between the brake pads and the brake discs. In this way, when the brake system is working, it will be stuck, and when the foreign matter runs into the gap of the brake disc, it will cause abnormal brake noise.