[GreenKeys] Lubricating Ball Bearing Motors

[Jim Haynes]

Also, sometimes we replace motor bearings.  That's pretty easy, as they
are a more or less standard size that bearing stores carry.  But sometimes
the replacement that is available is a sealed bearing rather than an
open bearing, which means it can't be greased.  So I guess when replacing
motor bearings, if the replacements are sealed, one should write a note
on the motor to that effect so that nobody tries to pump grease into it.

Some years back my then-housemate and I replaced a lot of bearings in
Model 28 motors, trying to get the noise level down.