Any Saginaw Power Steering Pump Experts?

Thanks! What do you think about my thrust play? I have some saying .020" is too much, and I have some saying that it's fine and allows room for expansion. When I did a rebuild, there didn't appear any areas in which play could actually grow...play seems to be "fixed" with these Saginaw pumps...

If it's too much, then I simply need a new pump. I did check the belt..no cracks or anything. I didn't flip it back over or adjust the tension though. I just removed the belt and the "knocking" noise went away. Here's a video of the knocking noise...you can hear it when I move my camera over to the PS side:

https://forum.e-bodies.org/gallerypics/videos/2011_02_02_19_12_12_37.mov

Pump is already rebuilt (new bushing and seals) and assembled. I didn't find any smoking guns. I'm just trying to make sure I've eliminated all possibility of what could be causing the knock sound. The knock sound I would guess is coming from A) shaft play being too big, or b) shaft play bottoming out due to the poor .070" offset of the crank and power steering pulley. It could be c) sticking vanes, but I doubt it because I'd expect more of a "click" sound, not a knock sound.