I apologize in advance if this post is too basic and/or covers material that you already know. I just wanted to throw it it there since you mentioned replacing all the bearings.
As long as the bearings and races are in good shape, you don’t have to replace them. I pulled some bearings from a small and infrequently used trailer that were toast, and have pulled some bearings after a decade of service and maintenance that were just fine.
I have a two axle travel trailer that sees a fair number of high speed highway miles, plus some dirt road and a lot of sitting in the off season. This past year (year 10 on the bearings) one of the Chinese bearings had a small ridge in the race, which I took as a sign to replace all four corners.
Replacing bearings is a bigger job than simply cleaning and repacking them. You have to drive the old races out with something like a long punch and install new ones. If you don’t have a tool to do that, a jumbo socket kit can work as bearing race driver. Just make sure not to nick the races. On the side of the road you are probably using the old race to drive in the new one, but it can be easy to get it stuck in there.
After you pull a hub and decide if you are going to the bearing store (look for truck and trailer parts stores) get a grease seal puller. I also get a spare hub and set of bearings, and several extra grease seals. When you repack it is best to replace the grease seals and having extras on hand will keep you from having to go to the parts store next time you do the job.
The extra hub and bearing set usually isn’t that expensive and it makes changing things out on the side of the road much easier. If you notice a hub running hot, it’s a lot easier to fix that problem with a spare hub with pre installed bearing races. I’ll pack the spear bearings and put them in the tub of grease I carry with the trailer stuff. This tip *would* have turned a 250 mile round trip and day job into a 30 minute pit stop when I lost the aforementioned bearing.
Last tip (which I never manage to follow). Don’t do the job on a 100 degree day. Good luck!
