1 S21-3502030 BRAKE DRUM ASSY 2 S21-3502010 BRAKE ASSY-RR LH 3 S21-3301210 WHEEL BEARING-RR 4 S21-3301011 WHEELSHAFT RR The automobile chassis is composed of transmission system, driving system, steering system and braking system. The chassis is used to support and install the automobile engine and its components and assemblies, form the overall shape of the automobile, and receive the power of the engine to make the automobile move and ensure normal driving. Transmission system: the power generated by the automobile engine is transmitted to the driving wheels by the transmission system. The transmission system has the functions of deceleration, speed change, reversing, power interruption, inter wheel differential and inter axle differential. It works with the engine to ensure the normal driving of the vehicle under various working conditions, and has good power and economy. Driving system: 1. It receives the power of the transmission shaft and generates traction through the action of the driving wheel and the road, so as to make the car run normally; 2. Bear the total weight of the vehicle and the reaction force of the ground; 3. Alleviate the impact caused by uneven road on the vehicle body, attenuate the vibration during vehicle driving and maintain the smoothness of driving; 4. Cooperate with steering system to ensure vehicle handling stability; Steering system: A series of devices used to change or maintain the driving or reverse direction of the vehicle are called the vehicle steering system. The function of vehicle steering system is to control the driving direction of the vehicle according to the wishes of the driver. Automobile steering system is very important to the driving safety of automobile, so the parts of automobile steering system are called security parts. Braking system: make the driving car slow down or even stop forcibly according to the driver's requirements; Make the stopped car park stably under various road conditions (including on the ramp); Keep the speed of cars traveling downhill stable.