I learned that the hard way. Was retrieving my boat at Belleville lake at Sandys Marina. Was driving a Ford Ranger with 4 wheel drive. Backed the trailer down the ramp,put on the e brake and loaded the boat onto the trailer and couldn't get the e brake to release. Had to put the truck in 4 wheel drive and literally dragged the boat and trailer up the ramp using only the front tires. Dragged the boat and trailer to a clear spot in the parking lot,disconnected the trailer and boat and had to drive across the street with the back wheels locked to a shop where they had to cut the e brake cable. If that shop hadn't have been across the street,I would have been screwed!