Power Steering Pump: Description

The Saginaw vane type power steering pump can be identified by the "ham can" shape of the fluid reservoir. 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 the vanes, oil is forced into the cavities of the thrust plate and through the 2 cross-over holes in the 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.