This past week, I hooked up my trailer to take pony to get coggins.  I'm heading down the road and a lady is frantically trying to get me to pull over.  She finally succeeds by cutting me off and motioning to get over, then comes running over telling me that my trailer is shooting sparks/fire from underneath.  Then we looked at the right front tire and it was not rotating but stuck in place causing the flat & sparks.  It was being dragged down the road.  Poor pony was wild eyed.

Has anyone had this happen?  I'm concerned that it will happen again and I won't know it, again.  That day I did have someone come over and work on that wheel because it wasn't really tight after the brand new spare was put on.  He re-did the bearings on that wheel and there is no more play in it.  It was unusually cold that morning as well.  Does anyone have any insight here?  Is it common for the trailer brakes to get stuck on the wheel like this?

The fact that the wheel was attended to before the problem started, sends a red flag. " He re-did the bearings on that wheel and there is no more play in it." When the wheel was removed, was the brake magnet, linkage or shoes disturbed? When the drum was reinstalled, is there a possibility that the star adjustment was over tightened? Was the axle nut and lock assy over torqued, causing the wheel bearing to over heat, expand and stop rotating?

If more than one brake were involved in the problem, it might be an electrical fault. Having just the one brake lock, one that was last attended to, would suggest that it was reassembled improperly and you now have a mechanical problem.

The whole assy should be disassembled and inspected, preferably by a different mechanic. He may need to source new brake parts or wheel bearings to alleviate the problem