Re: 1987 escort trailer bearings.
Well, if I understand you correctly, your wheel and hub fell off the trailer. Is that correct?
If that's the case, then the bearings should still be in the hub. What probably happened is that someone left the cotter pin out and the hub nut backed off, allowing the wheel and hub to come off.
Without seeing the assembly, it's hard to answer your question. What I'd do is pop the grease seal out of the back of the hub, and take it and the bearings to a bearing house, marina, or a rv place. There are numbers on the bearings, and they're probably standard bearings.
If you don't have the nut that holds the hub on the axle, temporarily take the one off the other side and take it in, too, so you can get a new one. There's a thick washer that goes between the nut and the outer bearing, so take that with you, too.
If the bearings and seal are gone, then you'll have to disassemble the other side to get the numbers and as comparison samples to take with you.