The bearings were actually easy to replace, no special
tools required.
The hardest part was getting off the nut that was holding the spindle
together.
Nothing to do with this drive (in fact I have never seen this in 8" drives)
but some direct drive 5.25" drives have a left hand thread screw holding
the rotor to the end of the spindle. The HD one in my PC/AT does, for
example. Do not ask how I found this out!
-tony