How strong are trailer brake magnets supposed to be?

[4570Man]

I had electric brakes on a 9 ton tri-axle trailer and with a 12k machine on the trailer I could lock up the brakes at 35 mph if I didn't adjust the gain on the controller correctly. It sounds like your magnets aren't working correctly.

My other 10 ton trailer will lock the brakes with my backhoe on it. This trailer another 10 ton will engage the brakes but it’s so light that for all practical purposes it has no brakes. I noticed some light fraying on one of the magnets but nothing on the others 2. I haven’t had the 4th hub apart. The brake pads are nearly new and there’s not much wear on the drums.

 

[ruffdog]

It would be suspicious that all the magnets became impaired at the same time though.

 

[4570Man]

It would be suspicious that all the magnets became impaired at the same time though.

I would agree to that logic but I’m at a loss as to what else it might be. And they didn’t necessarily fail at the same time. I just got the trailer and none of them work.

 

[bcp]

Magnet test:

Testing Trailer Brake Magnets for Proper Function | etrailer.com

Bruce

 

[fried1765]

Magnet test:

Testing Trailer Brake Magnets for Proper Function | etrailer.com

Bruce

Thank you for that Bruce.
Very helpful !

 

[nyone]

The maginet is only part of the brake system. The pivot arm and pads also have to move easily.
Usualy on these trailer drum brake systems by the time something wears out its more worth while to just put a whole new brake assembly on.

I went through this with my 2006 car trailer. Years i fought one brake not working properly. Finaly replaced all of them and they have never been better.

 

[Fallon]

The maginet is only part of the brake system. The pivot arm and pads also have to move easily.
Usualy on these trailer drum brake systems by the time something wears out its more worth while to just put a whole new brake assembly on.

I went through this with my 2006 car trailer. Years i fought one brake not working properly. Finaly replaced all of them and they have never been better.

Ya, that's the route I went. It's not that expensive to replace the whole assembly with shoes, magnet & what not. Good piece of mind that everything on vital safety equipment is in good shape.

 

[cat fever]

I had the same experience with my trailer/brakes.

I bought the whole backing plate. 4 bolts and the wire, never looked back. It was less money than messing with pads/magnets. I did both axles at the same time.

 

[woody]

I would agree to that logic but I’m at a loss as to what else it might be. And they didn’t necessarily fail at the same time. I just got the trailer and none of them work.

if the trailer is fairly new the pads need to seat to the drum the last trailer I bought got better with time and use. also look at the size of the wire that used on the brake circuit one of mine was wired with regular trailer light wire and after I rewired it worked better.

 

[woody]

I had a Ram pickup with a factory in dash brake controller, even on the highest setting, had very little trailer braking.
Same trailer I had used for years with aftermarket controller with no issues. Just for fun, hooked it up to the Ford
with factory brake controller, and it could once again lock up the tires when the trailer was empty.
Moral is, may not be the brakes, may be controller

My Ram has two settings one for light trailers and another for heavy, plus the adjustment for the controller.