Electric brake question Jocco needs help

Dealing with a trailer 3 axle electric brake (Dexter). Used to work good but now some of the wheels are not working like front axle. Back awhile we checked shoes and linkage and replaced as needed. To me this seems to be a electric issue controller box works but does not seem to control the brakes. I tested the magnets and they did magnetize. Can any of you give any suggestions? Bad controller box, drums wore out? As the Prophet once said "we need to dig a little deeper here"

My experience was with a 2 axle trailer. After lots of frustration, I discovered that the front axle was "gripping" tighter than the rear axle. In other words, if they don't all grab at about the same pressure, one of them will effectively "lock up" and then the controller sends a signal indicating an overload. Jack up the wheels, apply the brakes and check each wheel to see if they all require about the same pressure to make them turn.

On the ones I have had trouble with 99% of the time it is a ground problem at the drum area of the axle.

check your wiring and connections , you may have some corrosion or broken wires.

If you go to etrailer.com they have some videos of how to test the brake magnets. If you have 10-12 inch brakes, you can measure the resistance between the leads and it should be 3.0 to 3.8 ohms. No continuity at all indicates a bad magnet. I was getting uneven braking on a trailer that I had and found the bad magnets using this test. There are also amperage tests which you can find at the same site.

Trying to make all 6 wheels on 3 axles perform equal work can be unnerving. The arms that adjust spring action when a wheel rolls over high spots and curbs really make braking unequal. You soon wind up with glazed shoes on some wheels and worn shoes on others. To keep system operating half way right requier's total replacement of shoes on all axles eventhough some are hardly worn. To some extent,the same is true on 2 axle trailers so if local law allows,heavier brakes on one axle is better than lesser brakes on both axles.

If you have power to all the wheels I would suspect either out of adjustment or drums worn out. How many times have the brakes been replaced? I usually replace the drums with the third brake shoe replacement. To set the brakes, set them up til they are tight, then back them off til the wheel turns mostly free. You should still here the shoes sliding on the drum. Too loose and they won't grab like they should. Another thing is that the rear axles usually have less braking than the front as the power hits the front first, so they get the most and each one further down the line gets less. For hard used contractor trailers I would sometimes trade the front left and right rear brakes around mid season so they would wear even. On trailers that I build I usually bring the brake wire down to a central spot and split there so each brake gets close to the same length of wire.

Pretty much all the high points have been covered. I would suggest testing the coil resistance for each hub. Then, run a ground wire from the wheel backing plate to a clean spot on the frame for each backing plate. The ground return path needs to all be the same for even operation. Of course, the shoe adjustment must also be similar. I used to jack up, spin the wheel, adjust the starnut with the spoon until it just stops the wheel, the go two clicks backward. As long as they are even, it works pretty well.

Lots of factors effect the braking.

Trailers are notoriously hard on wiring, lots of shaking and bouncing, tends to break wires, wear through insulation. The more you can secure the wiring the better and longer it will last.

Using the correct type (automotive wire, it's more flexible than industrial wire), and size (14-12ga), solder and shrink tube every connection, secure and protect the wire away from sharp edges and secure tightly to prevent sagging, bouncing, and snagging, ground each axle, and try to keep each wire the same length from where the main wire splits.

And the brakes themselves need to be in good working order, clean and free of grease, and adjusted properly.

Also the suspension needs to be in good order. Shackles, eye bushings, spring mounts, proper geometry, all effect weight distribution, which effects braking ability verses sliding the wheel.

I don't think the controller is to blame, though there are different types of controllers. The proportional types work best. This type knows how hard you are stopping, and applies the trailer brakes accordingly. However, it still sends a common signal to all the brakes, it doesn't know which axle or wheel needs the most braking, or if one is sliding while the others are still rolling.

Hope this helps!

My dexter brakes recently had a hick-up. Each magnet checked out at 4 ohms. All 4 together measures one ohm. 6 magnets together, will be less than one ohm. So best to measure one at a time.

On my old trailer, I went to an RV place dealer bought one replacement magnet. It didn't work the same as old magnets. That wheel pulled harder than the others.

Primus? IQ Electronic Brake Control, for 1 to 3 Axle Trailers, Proportional . If something is wrong it will flash a code,( ol) overload, or (sh) short. It also has a digital display showing the voltage applied to brakes. It works great. A few times I had a pinched wire shorting to ground. Took some time locating it.

Good luck.

ground

You say some of brakes not working like front axle on 3 axle so as I understand it the other axles the breaks are working on. If so it means that the wire that comes off the main harnes has come disconected by breaking or corosion so that is where to look, not in the individual brakes. That main wire will have to seperate into 3 branches for each axle then at the axle they will seperate into 2 branches again. So if only one axle is not working it has to be in the branch of wire to that axle for it to be both on that axle, it could be either front, middle or rear of the branch that feeds that axle. But before the individual wheel branches.

jocco Just sold out 3 axle trailer and got a tandem. Know about keeping the brakes working on a 3 axle. Check the armature on the drum. This is what the magnet rides on. Has to be flat with no grooves. Magnet needs to be flat as well. According to Dexter you can turn these down a certain amount. The amount is on their website. Magnets can be sanded down flat too. My brother has a machine shop and puts the drums in a lathe and turns down the armature. Then to brake shop to turn the brake surface. One thing I got was an Infrared Thermometer and use the brakes and check temperature to see which ones are working. Lynn