Steering Gear: Description and Operation

The power rack and pinion steering gear has a rotary control valve which directs hydraulic fluid coming from the hydraulic pump to one side or the other side of the rack piston. The integral rack piston is attached to the rack, and converts hydraulic pressure to a linear force which moves the rack left or right. The force is transmitted through the inner and outer tie rods to the steering knuckles.

If hydraulic assist is not available, manual control is still possible, but more steering effort is required. Without hydraulic assist, the movement of the steering wheel is transferred to the pinion. The pinion's movement is then transferred through the pinion teeth, which mesh with teeth on the rack causing the rack to move.