Thanks guys.

Figured it out: The long/nasty to get to/invisible bolt under the alternator wasn't engaging the power steering pump bracket like it needed to.

1997 850 GLT Turbo with AC New (very frustrated) poster. Should have just paid someone (20/20 hindsight), but I (with great trouble finding the right bolts, and getting to a couple of those bolts) pulled the alternator, had it rebuilt and put it back in, but now the serpentine belt won't track prope...