Re: Brake trouble?
You have a problem that can be caused a couple of ways, either the brakes are dragging or the bearings are done, either way you have some work to do, the first thing I would do is get the trailer up on stands and start spinning tires, see if any of them are not spinning freely, if not then check the wheels for play laterally, if there is more then a little play you need to rebuild the bearings with new seals and grease, take the wheels off and see if the brakes are dragging you can hear them drag but to be honest I would just go ahead and rebuild the hubs anyway its sounds like the rear seals are toast, and if the brakes are hanging up then they could very well need a rebuild as well, good time to do it.
Heat in the hubs is somewhat natural but to much heat is not good, bearings will generate a small amount of heat if they are in good condition but a large amount of heat if they are done meanwhile a certain amount of heat will be transferred from the brakes to the hubs, drums and discs transfer different amounts of heat to the hubs due in part to they generate different amounts of heat within themselves as well as having more or less surface area to bleed off heat. Without having the trailer in front of us though its tough to say which scenario you are dealing with specifically, but to have a mechanic tell me the heat is generated by the brakes not engaging will tell me to find another mechanic.
So first step is to get your trailer into the air and spin them tires!