If you have a #10 Dexter 3500# axle
or a 3500# ALKO axle
the bearings and seals are pretty readly available. If you have an E-Z lube axle
make sure you get double lip seals.
Best to try E-Trailer or Eastern Marine both are on line trailer supply outlets.
The older 2200# axles (4 bolt) should also be available. I think the last set I bought for the older axles was from a Northern Hyd. store.