Troubleshooting Trailer Brakes that Hum But Do Not Lock Up

Question

Question:

Trailer brakes humm but dont lock on hard

asked by: Keith W

0

Expert Reply:

The humming sound you hear from your trailer's electric drum brakes is a good sign. It means that the brakes' magnets are being energized by the output from the trailer brake controller in the vehicle. Most likely your brakes aren't adjusted properly and that's why they aren't grabbing like they should.

When a drum brake is adjusted correctly there will be slight drag on the drum when you rotate it by hand. You should be able to hear and feel this drag. Try adjusting your brakes so that they drag slightly on the drum and then test the trailer with your vehicle.

We have a video that shows how to adjust the brakes, see link. At the 4 minute and 30 second mark you will see the adjustment procedure.

expert reply by: Jameson C

0

Answer 1

Hey Cary, so the correct size brakes to use for your axles would be based on the axle capacity. You can't switch between drum diameters without changing axles as there is only one size drum made for each axle capacity basically. So if you have…

view full answer...

Answer 2

Hey Martin, so the grease that is in the trailer hub part #AKHD-5475-35-K is a lithium complex so it would be smart to stick with that like the #DX64TR.

view full answer...

Answer 3

Hey Kirby, that really will depend on whether there was oil on any of the components. If there was any oil it's going to be a struggle to try and get it to clean itself and you may end up ruining the brake pads to point they never give you full…

view full answer...

Answer 4

It sounds like you may not have wired everything like it should be, particularly the ground wires. Each brake assembly is going to need to have a pair of wires coming out of it, with both having ground wires that are attached to bare metal surfaces…

view full answer...

Answer 5

There are a couple of things you can check to see why the brakes are not working properly on your trailer after replacing the shoes and hardware. I recommend first ensuring that the brake assemblies are grounded properly. It's possible that while…

view full answer...

Answer 6

The humming sound you hear from your trailer's electric drum brakes is a good sign. It means that the brakes' magnets are being energized by the output from the trailer brake controller in the vehicle. The issue with the brakes not applying…

view full answer...

Answer 7

Typically you will not see any voltage on the trailer side of the connector. The 12-volt charge line circuit is generally the only one which will have power depending on if there are diodes in the wiring to prevent power from flowing back through the…

view full answer...

Answer 8

We have an entire help article dedicated to testing trailer brake magnets that I attached for you to check out. You can test for resistance like you described. There is a specified range of Ohms that should be present depending on brake assembly…

view full answer...

Answer 9

They sure are. The buzzing or humming sound means that the magnets that grab the armature surface of the brake drum and actuate the brakes are active and are receiving power from the brake controller. The humming noise does not indicate a problem.

view full answer...

Answer 10

Trailer brake magnets will hum when activated. The wires are also not polarity sensitive so as long as one is grounded and the other has 12 volts you'd be totally fine. Based on what you have described it sounds like your setup is good as-is.

view full answer...

Answer 11

I would check the magnets for wear before going on to test them with a meter. If the magnets show abnormal wear or if you can see the windings beginning to show through the friction surface of the magnet then they will need to be replaced. To further…

view full answer...

Answer 12

When trailer drum brakes are activated you should be able to hear a humming sound. I am not quite sure I would describe it as musical, but it sounds like they are functioning on your trailer. Have you tried testing the brakes to see if they function…

view full answer...

Troubleshooting Trailer Brakes that Hum But Do Not Lock Up

Product Page this Question was Asked From

Featured Help Information

Miscellaneous Media

Continue Researching