Trailer Brakes Will Not Lock Up with Output Voltage Over 13 Volts

Updated 09/22/2015 | Published 09/21/2015

Question:

Why does it seem that I cant get my trailer brakes to lock up? I can see that the trailer is putting out 13.8V to brakes? I have tightend the brakes down where they drag pretty more then you would want and they still do not lock up? Any suggestions?

asked by: James B

Expert Reply:

If you are getting 13.8 volts at the magnets then that is more than enough. Maybe too much like there is a short somewhere. I recommend testing the brake magnets. First you can inspect the magnets and if you can see the copper windings coming through then the magnets will need to be replaced.

To further test the magnets electrically you will need your volt meter and a separate 12 volt battery. I have included a link to our help article on testing brake magnets for you.

Brakes can also be weak if there is any grease on the pads on inside the drum where the pads touch. Grease on the pads is pretty much impossible to eliminate so they shoes would have to be replaced if that is the case.

Also make sure that the magnet ground wires are attached to clean bare metal surfaces near the magnets for the best results.

expert reply by: Michael H