I have a 2 axle trailer with electric brakes on all 4 wheels. One of the brakes gets hot (not the bearing, I checked). If I back the trailer into its parking place and jack it up, I can spin each wheel either direction and there is very little drag. If I then connect 2 NiMh AA cells in series (nominal 2.4V)to the brake wires on the plug, the 3 wheels with good brakes are very hard to turn and the wheel with the bad brake is a little easier to turn, but the brake is definitely working. If I then disconnect the batteries from the plug, the 3 good wheels spin freely again, but the bad wheel depends on which direction I turn it. If I turn it forward, the brake keeps dragging about the same as if I had the batteries connected and it will keep doing that until I get too tired to turn the wheel. If I turn the wheel backward, there will be a little drag for about 1/8 of a revolution, the the brake will release, and the wheel will spin either direction freely. I can duplicate this pattern over and over. I can't see anything wrong with the brake parts except that the return spring seems to be made of thicker wire than the other 3 brakes. That probably accounts for that brake being slightly weaker. I suspect that the former owner put on a stronger spring to try to fix the dragging brake problem. There is not a lot of rust and the shoes slide freely on the backing plate. The lever that actuates the brakes swings easily and pushes the shoes out at the top as it should. I tried carefully lubricating all the points where metal slides against metal, but it did not help. Does anybody know or suspect what the heck is going on here?