Integral Power Steering Gears

A representative of an integral power steering gear is used on certain General Motors rear-wheel drive cars and on American Motors four-wheel drive. This power steering gear uses a recirculating ball system in which steel balls act as rolling threads between the steering worm shaft and the rack piston. The key to its operation is a rotary valve that directs power steering fluid under pressure to either side of the rack piston. The rack piston converts hydraulic power to mechanical force. The rack piston moves up inside the gear when the worm shaft turns right. It moves down when the worm shaft turns left. During these actions, the steel balls recirculate within the rack piston, which is power assisted in movement by hydraulic pressure. (See also Manual Recirculating Ball Steering)