And PLEEEAZE don't use an old cotter pin or, worse, a nail! Get the correct
diameter and length cotter pin to fit the hole in the spindle. They are
cheap, get enough to do the hubs again.
Bearings should be washed in a parts washer that has fresh clean fluid.
Inspect the races, rollers and cages closely for any pits, spalling
(flaking) or wear of any kind. Rolling bearings such as roller or ball do
not wear during their normal service life. Any wear calls for replacement
of all parts: cup (outer race) and roller assembly (rollers, separator or
cage, and cone (inner race).
Then a bearing packer ($9.95 at parts stores, $2-3 at harbor freight) should
be used, though if you are diligent you can pack them by hand. Do not fill
the hub with grease. Doing that is only for boat trailer hubs that get
dunked. It may come out past the seal and ruin your brake linings. The
assembly should be full of grease and the cup should have a liberal coating.
Smear a light coat of grease on the bores of the cones and on the bearing
seating and seal riding surfaces on the spindles.
Don't let any brake cleaner get on the magnet. It may dissolve the
insulation on the windings. Only the linings and drum should be cleaned with
brake cleaner.
When replacing the oil seal fill the groove in the seal lip with grease. It
must be pressed in squarely to avoid it being loose or leaking.
Al