Just pulled the pump off the 81 Jetta I just picked up. It's leaking out the CS lever shaft, so I was planning on resealing the whole pump, but I noticed the shaft has a fair bit of play (not sure how much, I didn't try to measure it) but it's definitely noticeable. The main shaft seal is not leaking, but I noticed the belt had been running off the outside of the pulley. Could this be caused by a worn bushing? I checked a few other pumps I have around, and they all seem to have play too, but maybe not as bad, so I'm wondering, how bad is bad?
There's a good thread on this with pics and specs if you search.
I think that belts tend to try and run tighter, or to higher ground like Andrew said.
If the play is obviously noticeable it's probably worn out.