I have the motor disassembled and now I can see why they claim
electric motor bearings should last lifetimes barring lubrication
failure, arcing , or contamination, these things are massive.
It looks like dried flakes of coolant or perhaps the corrosion the
coolant did to the metal ends of the motor was the culprit, the grease
itself was there without being excessive. The motor shaft end bearing
has a bad feel and a little looseness and I believe it was just enough
to cause the cup wheel to pound in a few spots and glaze up. I think
when I put the thing back together I will make some sort of "flinger"
from coffee can lid plastic just far enough from the motor housing to
not rub. Although I can't complain about the service this thing has
given me.

Thanks again for all the help.
Tom