I am working on a 2005 kaufman 20 foot equipment trailer, and pulling it with a 2005 f-350 with the built in brake controller. I am baffled at why I can't get this thing to work right. When I got the trailer the brakes were very weak. I pulled the wheels and found that it was greased so much that it pushed oil from the grease past the inner seals and coated the magnet face and brake drum faces, but the shoes were dry. I cleaned the oil with brake clean, cleaned the magnets, and adjusted the brakes. They work now but are very weak, my test is with an empty trailer it should drag the brakes, at least on my gravel driveway but it will barely stop the truck at idle.

The next step was to replace the magnets, they seemed to have grease in them and it seeped out again, so they were replaced, and it seemed the same, very weak brakes.

Third step was to adjust the brakes very tight, had a good amount of drag on them. Did'nt seem to help. I took it on a 20 mile and back drive to deliver a truck and they got super hot, could not really touch the hubs.

Fourth step was pulling the drums again and sanding the brake shoes, mabye they were glazed over. Also backed off the brakes so they just have a slight drag. Still very weak, but delivered a second truck to the same place, this time the front axle hubs were hot but you could touch them, could not put your hand on either rear hub. Also used a temp. gun, rears were 200 degrees. They were hot after the first 20 miles, not much braking. Then let them cool, drove home and turned the brake controller to 0, this is when I got the 200 reading. Also when I pulled the dust cover on the rear it popped off and shot super hot grease at me, and now I have a little play in the bearings.

I am at a loss now as to what to do, and mabye the bearings are fried to? I get 10 volts to the brakes with the ford controller maxed out to 10, is this what I should get? Also what is the correct procedure to torque the bearings, I just snug them down till I feel a drag on the wheel, then back off mabye a quarter turn and bend the locking tab down.

Sorry for the long post, but I'm about to use the trailer for target practice, tired of dropping money on it. Any help is greatly appreciated.

 

Just to get everyone on the same page, when you are moving and you activate the brake controller manually, you can not feel the trailer brakes working?

Since you have done a great of work on the brakes already, one of the first things I encourage folks to do, with the trailer connected and the seven pin out of the truck is to pull the break-away switch on the trailer, with a good battery on the trailer. When you do that, the trailer brakes will be fully engaged. Can you pull the trailer when you have the break-away pulled? The trailer should be stuck fast!

Since the trailer brake controller has an accelerameter, it works the trailer brakes in proportion to how hard the truck is stopping and it is very difficult to detect its action, even when it is working fine.

Now I note you have only 10 volts to the trailer from the seven-pin, so my thought would be the problem is more likely a grounding problem between the truck and trailer, which is very common problem. I would expect to see a higher reading. Doing as I suggest above takes the trailer out of the equation as you are activating the trailer brakes using only the trailer system.

If the trailer brakes are working, with the break-away reset and the seven-pin plugged back in, now take a jumper cable and make a good connection between the trailer frame and the truck frame. How do the brakes work when you do that?

Steve

 

I have tried with the brake pedal and the manual lever on the controller. Also I have tried the break away, which is also new, and it still rolls. it does have resistance, but not much. when I jack the trailer up I can hear it working, and when spinning the wheel by hand and apply the brakes it stops instantly and cannot turn by hand. I re-did the ground on the trailer and it works fine, will have to check the truck ground, but it is working fine with our other trailer. I will also check to see what voltage I get from the break away box and disconnect the cable from the truck tonight and see what it does.

Any idea on the overheating issue? I have worked on trailer brakes alot of times in the past and never had any issues, this one is just baffling me.

Thanks for your help.

 

How old is the trailer and it's brakes? YOu may think about replacing the pads and magnets or completely rebuild the brakes on the trailer. The break away should make the wheels STOP completely when applied. Check the voltage on the connection to the magnets with the break away applied. Could be bad connections there... either or both sides.

 

Do you know how to do an amp check to see how many amps the brakes are drawing? You should have a 12 amp draw when the brakes are full on. If you have the amp draw and the wheels still are not capable of holding the truck back the issue is mechanical with the brakes. If you have less draw, there is a bad connection somewhere. This is testing using the break-away with a fully charged battery. If you have a clamp meter, this step takes less than a minute.

It would be helpful if we can focus on one thing at a time.

Let us know,

Steve

 

I will check the amps tonight, the magnets are new, the old ones were so soaked with grease that I could not get them cleaned out, but I had the same symptom with weak brakes before I changed them. The trailer is an 05 Kaufman 14k deckover. The brake shoes look great, plenty of meat on them.
thanks again for the help, I'll either fix it or blow the thing up.

 

It will take a bit of step-by-stepping, but each diagnostic step gets you closer to the answer. If you have a good power source and new magnets and you do not see 12 amps or close to it, it has to be a loose connection or ground at the trailer. I am trying to leave the truck out of the equation so we can work in halves as it is possible to have more than one problem.

When I work on systems, I try to always use my own good known power sources thus using the battery or jumper box at the trailer. It is pretty simple to troubleshoot the circuit doing that.

Since you said you get some stopping power at the trailer wheels, but not enough, it sure sounds to me like a power issue, but if you get a full amp draw, I would guess the shoes need adjusting as there is no way to make the magnets draw any more than their max.

Don't forget to put the pin back in the break-away so you don't melt the switch.

Steve

 

well so far I have disconnected the plug from the truck and pulled the disconnect, I get a 10v reading at the brakes, and still weak brakes. Now I have connected a good 12v battery straight to the brake system to eliminate the truck and disconnect. When I check the voltage at the brakes I'm getting 10v still. When I check it at the battery I get 11.9v. I allready replaced the brake wire on the trailer, now I think I'll replace or at leasy run a temporary ground to rule that part out. I still have to check the amps, borrowed a clamp meter but I don't think it's working. Have to break into the wires and use my regular one. Time to go out and play in the dark.

 

It should not be too hard to put your meter in series with the break-away, if you have the alligator adapters for your leads.

Steve

 

well I don't have alligator clips, did not realize I could check the draw at the breakaway. I took a 12v battery and connected the positive to the new hot wire I ran to the brakes, and ran a new ground wire from the brakes directly from the brakes to the 12v battery. I got 12v at the battery, and 10.6 at the brakes, then I disconnected all the wires and ran a 12v to each axle by themselves, and a ground straight to the battery. I got 11.3 volts this time on each one, but the brakes would not hold, they were applying, but not holding.

I am convinced the electrics are fine, I still have to check the amps, will do that tomorrow, but what else could there be? Can the surface the magnets ride on be too smooth? They were ran along time with grease on the magnets and on the drum where they ride. Right now I have the brakes set so there is allmost no drag, I had them with a decent drag but they just pulled all the time and got hot fast. and still with the overheating, could something be applying them or them dragging and activating the brakes when I am driving?

Thanks again for the help

 

It does sound like the electrics are fine, although the amp draw is the best test, and is the only way techs are trained to test trailer brakes. At least you know you connections are intact given equal voltage at each wheel.

If the electrics are good, that leaves only the mechanical side of things as wiring directly as you did, you bypassed anything else.

On the mechanical side, there are only two things, components or adjustment (at least that is all I can think of), but did you say even with more drag on the adjustment, the brakes were still no good? If that is the case, all that is left are components. Do you know anyone who can take a look at this setup with a wheel off, who is familiar with brakes? Sometimes when I am working, I get too close to a problem and can't see something obvious. Then I have to take a break and read about the system for a night on the Internet. This shouldn't be this hard, so my thinking is it is something simple. I can't think of anything else it can be.

Steve

 

are there any differences in the magnets, like is a magnet for a 7k axle different then one for a 3.5k axle? I will have to see if I can find the old ones, not sure if I threw them away for now. The trailer store I got the magnets from just matched them up by sight with another magnet they had.

 

I don't know of any differences. If they fit and draw 3 amps per wheel they should be good to go. I am used to thinking in terms of 12 amps because most of what I work on has two axles.

Steve

 

Hi all,

Read all posts on the problem, Three things cross my mind, Could the drums be glazed and the shoes on wrong or too small. Not trying to be a smart aleck just trying to help.

Bob

 

All input is welcome. I thought about those things too, but since the OP said he had brake experience, I figured he likely got things together in proper order. I am not sure too small a shoes would mount up. Shoes installed correctly is important for sure.

I certainly could be missing something in my posts I know and if the electric is good, It has to be something with the components or mounting. There's nothing else left I can think of.

Steve