For the engine (or motor) output part of the mechanical energy into pressure energy, and under the control of the driver, the steering transmission device or steering gear in a transmission part to impose different directions of hydraulic or pneumatic force, to help the driver to apply insufficient force of a series of parts, called power steering gear Motor power steering is when the driver moves the steering wheel at the same time, the motor under it starts Rack and pinion power steering is where there is a hydraulic pump next to the engine, and the engine drives the pump The electro-hydraulic power assist is a combination of the first two and is the best steering power assist on the market today The structure of the steering booster is very complex, and the general person can not be repaired. If the maintenance is in place, it is not easy to break. Note: you should always check the oil in the oil cup, not lower than the lower limit of the dipstick. If the booster loses oil, the pressure pump may be scrapped. Two, change the oil regularly. Three, you can't kill the direction. Try not to turn in place. The power comes from the engine, the truck has no other power, only hydraulic booster pump, generally installed on the flywheel housing, driven by the crankshaft hydraulic pump. Some are mounted in front of the engine and driven by a belt, but these are usually modified. The power steering system is composed of a set of power assist devices on the basis of the mechanical steering system. Steering oil pump 6 is installed on the engine, driven by the crankshaft through the belt and output hydraulic oil. The steering oil tank 5 has inlet and outlet pipe joints, which are connected with the steering oil pump and the steering control valve 2 respectively through the pipe. The steering control valve is used to change the oil circuit. The mechanical steering gear and the cylinder block form two working cavities, which are connected through the oil channel and the steering control valve respectively.