Here's how a hydraulic steering rack works to turn the wheels on your car.
Hydraulic steering has been used for decades to provide assist to drivers turning the wheels of especially heavy vehicles.
Fluid is pressurized by a hydraulic pump and is sent to the rotary valve via the high pressure hose.
Depending on the direction, the fluid is pushed into the opposite side of the cylinder housing, pushing the piston. The piston is connected to the rack, which connects the tie rods and hence the wheels at the steering knuckle.
Its all explained in the video, Thanks