Sounds like the coupler is still pushed in, after you backed up the trailer. Have you tried pulling the coupler back out after you unhook the trailer. That should disengage pressure on the brakes.
Sent from my iPad 2 3G using Tapatalk
09 X2, MCX 350, VDig, PP, Heater, Shower, Bow Filler Cushin, Bimini, Wake Plate, 2 Tower Speakers w/Forward integrated docking lights, Tandom Low Profile Trailer