While I do not know your particular vehicle/design of the hub assembly, my experience tells me that when the bearings go bad with a hub assy that the only thing you can do its to replace the hub assy. As far as I can tell, the wheel/hub assy came into being when front wheel drive became the norm. Until then, the bearings were individually replaceable as were the bearing seals. I have replaced a few of the hub assemblies and they can be as easy to replace as individual bearing to extremely ******* difficult. From NAPA they cost close to $100 each. The first vehicle I replaced them on sounded like I was going to loose a wheel. But i could not feel any wear in the assy after removing them. The second one I replaced did not sound bad, but the wheel shake was bad and I could not believe it had not come apart.
Hopefully you can find some usefull info here.