This is a quick question that is part of the problem I have already posted with my brake controller in the hitch/brake forum.
My left hub was too hot to keep my hand on for more than 2 seconds after towing the 13' Burro 1 to 1.5 hours at 60mph. The bearings are new, they checked out with lots of grease, when jacked up, the wheel turned freely and the brake pads were not showing wear.
What else could cause the wheel hub to be so hot?

Some of the things I've seen from other posts include:
1. Are you SURE the grease is fully packed around the bearings? Sometimes it's just surface-packed and not really filled completely in the entire cavity.
2. Are the new bearings the right size?
3. Could it still be the brakes? Try driving with them adjusted wide open and disconnected from the controller so they can't possibly activate and rub. We had a 1978 13' Burro and didn't really need the brakes, so you should be safe driving for a while without them.

You are correct that the hub shouldn't be that hot from driving. Good luck with the investigation!

Thanks Kevin. I was wondering if I would be seen as silly if I ask the guys at the repair shop to just open the hub and repack the bearings JUST IN CASE. Then they can also double check that the bearings are the right size, although I would think they would be the same size on the left as on the right and the right side hub was only slightly warm. Now I am going to call and have them repack the bearings while they are already working on the wiring.

If the nut that holds everything together is overtightened could also cause excessive heat (or too loose too). Everything needs to be "just right". Good luck.

Anne
Check the hub nuts. They should be set up just tight and backed off 1/4 turn before inserting the cotter key. If they are to tight they will definitely cause the bearing to over heat. While you are at it, better regrease the bearing. If its that hot theres a good chance the grease was cooked out.

Have them check the seals.That's the first thing to go when they get to HOT.

You can narrow the search down on whether it's the brakes or the bearings fairly easy ....... take it for a long enough ride to get it hot again and then stop and get out of your vehicle quickly and feel the center bearing hub first and then stick your finger thru the wheel spoke and feel the outer edge of the brake drum. Whichever is hotter is where the problem is coming from. If you wait too long the heat will have time to spread itself out and everything will be the same temperature. Just a guess but if it's the brakes the shoes on that side could be installed backwards ( I believe it's larger pad to the rear and smaller pad to the front. You could also jack it up on the bad side (hot side)and carefully spin it while the tow vehicle running is hooked to the trailer and plugged in see if there is any drag on that wheel while it is running........ Back a while ago i had a problem with both my drums getting hot and the cause was i had "Boost On" on the prodigy controller and while driving around in the city the trailer brakes would grab first and get unusually hot..... I turned "Boost Off" and all is fine now.
This is just a "Free guess" which costs nothing to try..... hope it works for you.
Joe

Last time I had a wheel showing signs of getting hot, I backed the bearing nut off by one facet, and re-inserted the cotter pin. It had a little more play than I liked, but it was something I could live with.

BTW, that was on a utility trailer that had no brakes, so there was only one possible issue to deal with.

YMMV

Hi
I had such a problem a few years ago with my Boler 17'.
That came from brakes.
Electric brakes work with a magnitized arm inside the brake drum that moves backward as the magnet sticks on the inside of the drum and that causes the brake pads to apply friction on the side of the drum.
As my drums had been turned, the inside diameter of the drums became larger than it is on new ones. So the magnetized arm runs farer backward than with new drums..... So they could hang up on the structure inside the drum, letting pads pressed on the drum .
I had to change drums to solve the problem.
Hoping this help.

Well, I had the guys at Crossroads RV take the hub apart to double check. Guess what!? The grease was only on the outside of the bearings, not all the way in! So they repacked and fully greased the bearings and the hubs were cool all the way to southern Arizona (~1800 miles). However, since i am still having some issues with the brake controller (posting in the towing forum), I think I will get some help from someone here to look more carefully at what is going on with the brakes to make sure everything is properly installed there.
Thanks for all the help!