The brake disc is made of alloy steel and fixed on the wheel, which rotates with the wheel. The slave cylinder is fixed on the bottom plate of the brake, and the two friction plates on the brake caliper are installed on both sides of the brake disc respectively. The piston of the slave cylinder is driven by the hydraulic pressure transmitted by the oil pipe to press the friction plate against the brake disc for friction braking, which acts like clamping the rotating plate with pliers and forcing it to stop.

The disc brake has the advantages of fast heat dissipation, light weight, simple structure and convenient adjustment. Especially under high load, it has good high temperature resistance, stable braking effect, and is not afraid of mud and water. When driving in winter and bad road conditions, disc braking is easier to stop the car in a short time than drum braking. Many small holes are also opened on the brake discs of some disc brakes to accelerate ventilation and heat dissipation and improve braking efficiency.