Troubleshooting Right Side Brake Magnet on Single Axle Utility Trailer

Question:

I have a Hudson, 12foot single axle trailer with a 5,000 GVW rating. 10inch X 2 1/4 hub. Having trouble with RS brake not working. LS works ok. Magnet does not energize on RS. Think about replacing both brake assembles. Regarding the magnet input wires. Will no hold pliers. I have 12 volt to the RS magnet, The other wire needs to go to trailer ground? 4 dots are still showing on magnet and magnet looks good. Can I just ground the non-12 volt wire directly to ground to test my ground to that magnet? I am using a 12 volt power Pak supply to the emergency brake supply circuit to do my testing, not to tow vehicle. Is this OK? It does lock up the LS brake as intended. I am thinking RS magnet is bad. I could switch magnets and re-test but thats a pain. Probably keeping trailer as I just repainted it and use it sometimes to transport my side by side and tractor equipment, etc.. Suggestions.

asked by: David W

Helpful Expert Reply:

Each brake magnet should have 2 leads, one to power, one to ground. Most of the time, folks just ground the magnet to the trailer frame, and use the trailer frame itself as the ground circuit.

I'd recommend finding the point where the wiring makes a run to the right side, and test the supply wire for power after the junction. Even if the magnet is bad, you should still show power on the wire feeding the magnet.

I'll link you to an FAQ article that explains how to test brake magnets to see if they're still good. Usually, a visual inspection will tell you all you need to know. Look at the face of the magnet that rides against the inside armature surface of the brake drum. If you can see any of the copper wire that's encased in the magnet, the magnet is bad and should be replaced. I have seen a few cases where the brake wire got almost completely severed at the point where it entered the magnet, so that it appeared that the power was reaching the magnet, when it really wasn't.

expert reply by: Mike L