Power Steering Pump O-Ring

[truckster]

I'm installing my Redhead steering gear this weekend. I have a leak from the PS pump that I want to fix at the same time. It's leaking from the adapter (the adapter that goes into the pump housing) and I suspect the O-ring in there is the source of the leak. It's not the O-ring to the hose (I'm using flare fittings). I can't find a size for the O-ring and I want to make sure I have on on hand when I take it apart. Anyone out there know the size?