Generally speaking, how can a car wash hurt a brake disc with a material as hard as a brake disc? In fact, in our daily use of braking, the brake disc will produce a lot of heat because the vehicle decelerates the friction, the temperature will be very high. At that time, the owner chose to wash the car in the auto beauty shop. Before the brake disc could cool down, cold water was sprayed on the brake disc. When a steel brake disc is not cooled naturally but cooled quickly with water, heat expansion and contraction can distort the steel brake disc and cause serious cracks. After the brake disc is out of shape, the vehicle will have a noticeable jitter when the brake is applied, even if the brake is off track!