If you have a small 1/4 ratchet its actually quite easy - there is actually plenty of room to ratchet it back and forth in there (you just have to locate it by feel).

One thing to keep in mind for the people refurbishing their PS pumps is to take care to let the small vanes keep the position they are already in (either mark them when removing them or use tape to old them all in place.)
I didn't do this, and the result was that my refurbished pump failed after a couple of months - i suspect the failure mode was that the vanes no longer slide freely and got stuck in place, reducing the overall pump pressure.

 

Vains? I am refurbishing it and have taken the pump out, but have not started to disassemble them.

 

Its a sliding vane pump, so it has lots of tiny vanes that slide freely in slots.
I removed mine without marking them when i took out the shaft to replace the seal - i suspect that was the reason it failed after, since they didn't slide as freely in their new homes, leaving some of them to eventually get stuck, reducing the pressure.

 

It was probably the burned in wear pattern of the original outside vane edge matching the wear on the outer inside radius ring

so the vanes would have to be installed with that outside worn edge including if that edge is rotated 180 degees

This from someone who has not taken one apart