Rear Wheel Bearings -> 5kS

[kauffman@IMAP2.ASU.EDU]

Has anyone had to replace the rear wheel bearings on their non-quattro
5kS?  If so, how many miles did the old ones last?  Haven't confirmed if
they're bad yet, but I'm pretty sure they're the culprits (a low-freq
rumbling from the back of the car that has gradually increased over the
last 3k miles, real loud around 50 to 55 mph, disappears on sweeping
left-handers).  Thought it was a poorly-wearing tire at first, had a
rotation done, no diff.  Just wondered if this was common...

TIA

Karl K.      '86 5OOOS  136k mi
Mesa, AZ     '79 Fox  146k mi