Electric Trailer Brakes?

do not play around take it to qualified brake mechanic

steve
March 2011

The electromagnet doesn't actually do the braking, when it sticks to the drum it causes a rotation that moves the brake shoes to push on the drum. Similar to the brake wheel cylinder of a car with drum brakes. You should hear that magnet click loudly if you apply 12v to the two wires that go to each wheel. That magnet actually wears down till it needs replacing, and is probably the most common fault. My local trailer supply Co. sells the magnets, brake shoes, retaining clips, etc. I was going to buy magnets and shoes, however for about $40 more they sell all of it with new shoes, springs and hardware mounted on a backing plate as a complete assembly with connection wires, ready to go. I went that route. The plate is held on by four bolts, very easy access. Took me 15 min per wheel to remove the old and mount the new plate assembly, connect two wires and I was done. (well almost done, turn the adjuster until the new shoes almost touch the drum as you install, and then final adjust when the wheel is on).

Leslie Bates
March 2008

I place the trailer on jack stands. This way I can spin the wheel and hit the brakes to see if thy stop. If they don't, then I use a circuit tester to make sure the wires are hot. I also use a board or wrench or hammer or whatever will wedge between the seat and the brake pedal to hold the brakes on while I check the wiring and the ground connections.
The brakes consist of an electromagnet that sticks to the drum when activated. It has two wires on each wheel, one hot and one ground.

David Wood
July 2007