Power Steering Pump: Description

The Saginaw vane-type power steering pump can be identified by "ham-shaped" fluid reservoir can. Internally, rectangular pumping vanes carried by a shaft driven rotor move fluid from intake to pressure cavities of cam ring.

As rotor begins to rotate, centrifugal force throws vanes against inside surface of cam ring to pick up residual oil, which is then forced into high pressure area. As more oil is picked up by vanes, oil is forced into cavities of thrust plate and through 2 cross-over holes in cam ring and pressure plate (which empty into high pressure area between pressure plate and housing end plate).

Filling high pressure area causes oil to flow under vanes in slots of rotor, forcing vanes to follow inside oval surface of cam ring. As vanes rotate to small area of cam ring, oil is forced out from between vanes.