Hi Tony,

I have replaced a couple of these because of poor starting faults.
The inner casting appears to wear and the vane pump will not generate any cavity pressure at cranking speed.

You could try a gentle tow start as long as you know all the mechanicals are in good order.(you don't want to mask a mechanical fault through towing)

The higher pump speed normally generates the correct cavity pressure if it is the pump at fault.

Regards mark