Power steering pump PRV, what type is this one please?

[Chris Wilson]

Hands up, it's not from my tractor, it's from a Toyota road car PAS pump. They give "issues" and I suspect the conical brass gauze filter shown gets blocked. The factory manual gives no detailed description of how the PRV works internally. It's in the sliding vane rotary pump casting itself, which uses a remote fluid reservoir. Failure mode is zero power assist, and zero fluid movement in the remote reservoir, which also houses the return hose stub from the steering rack. So I assume the valve is allowing fluid to recirculate within the pump's casting in such a way no swirl is evident in the fluid reservoir mounted 6 inches above the pump itself on a rubber hose.

Can anyone say why the valve internally looks like it may be two piece and how the 2 ball check valves might work please? The best illustration of the valve I can find is blown up at http://www.gatesgarth.com/valve.jpg Many thanks.

 

[oldnslo]

I presume that you are referring to what is called the flow control valve in the attachment.

Can you trace the flow path in the pump housing? I.e. determine which ports connect to each area of the valve? It is hard to tell from the sectional view which components can move and how far the could move.

based on the screen location i would suspect that this is the inlet port for flow.

 

[bigdeano]

Generally the internal parts of the flow control valve spool are the pressure relief valve. The ones I've seen are pressed together, so you can't get in there. If you can clean the screen try that. Rebuilt pumps aren't a lot.