I have ripped up the board sensors trying the "CD on the center bearing" trick but now I'm older and wiser. BTW, three cheers for the Orion support team who sent me a new AZ encoder assembly free of charge (I can imagine them saying, "yep another one tried the CD").

I measured the thickness of the teflon pads and work within plus or minus a baby's hair of that. So far so good.

It sounds as if DMGRIFF may have gotten a bad bearing. Another possibility is that it is not centered and so begins to bind through some of it's travel. I was concerned about lubricants holding dirt also and used graphite dust (look at a sewing shop) to lube the susan bearing and that seemed to work just fine.