Trailer Brakes Will Lock Up with Trailer Sitting Still but are Weak when the Trailer is Moving

Question:

Enclosed RandR dual axel trailer. Brakes on all 4 wheels. Sitting in the driveway the brakes seem to work fine. manual override locks them up. the problem is as soon as i start driving, the brakes a weak and manual override will not lock them up? Cant seem to find the problem.

asked by: Brian T

Expert Reply:

When a trailer isn't moving the brakes will seem to work great because it isn't moving and when testing them sitting still the wheels are generally off the ground so there is no weight or momentum pushing the trailer forward.

Nine times out of ten when trailer brakes are weak it means they need to be adjusted. To see how to manually adjust trailer brake assemblies check out the video I attached, fast-forward to the 4:35 mark of the video. I recommend using adjustment tool # W80630 which was made for adjusting electric trailer brakes.

It could also be the wiring to the brake magnets or the magnets themselves. Inspect the power wires to the magnets and look for pinched, frayed, or damaged wires and fix as needed. Make sure the ground wires are attached to clean and corrosion free bare metal surfaces.

You can visually inspect the magnets and if you can see the copper windings coming through the magnets will need to be replaced. To further test the magnets you can follow the help article I have linked. I have also included some help articles on testing and troubleshooting brake controllers for you.

expert reply by: Michael H