RV Trailer Brake Mystery

[BHoerling]

Hi All

I have the following problem with our RV trailer brakes. All components are new and the brakes are functioning okay. The problem is that when applying the brakes to come to a slow stop, the left rear hub gets too hot to touch. The other hubs can be touched with no problem. I have checked the current at each wheel, and they read about 3 amps and the brakes are wired in parallel and read 12 volts. So on a test run today we disconnected the power cord to the trailer and took it on our 10 mile test run. I used the exhaust brake on the truck to assist in stopping the truck/trailer. No hot temps on any of the trailer wheels or hubs. So that tells me that there is not any heat developing from friction in the area of the spindle/bearings. So we hook the power cable back up and return to the garage. The wheel, hub is once again hot. Not sure what the temp is as I do not have a cordless thermometer. Any suggestions or just plain help would be much appreciated.

Thanks

Bob H

 

[Ragain]

Try backing off the automatic slack adjuster 1 turn on the problem wheel and the do the same brake check as before.

 

[CPG]

You never mentioned if your trailer has Hayes or Dexter brakes. The Hayes has only one brake shoe spring whersas the Dexter has two.

Best to remove the hot wheel and check for overheated springs or too close an adjustment.

 

[CPG]

You never mentioned if your trailer has Hayes or Dexter brakes. The Hayes has only one brake shoe spring whersas the Dexter has two.

Best to remove the hot wheel and check for overheated springs or too close an adjustment.

 

[BHoerling]

Thanks guys for your feedback. We have the Dexter axles on a Sunnybrook trailer.

 

[Tractorat]

Well, Im certainly not a brake expert. But I have had the same experience on my 1988 Wilderness TT. It always has turned out to be a burned magnet.

 

[BHoerling]

Thanks Tractorat, but we have installed new magnets in trying to resolve the problem, no luck. This morning I was able to get my hands on a cordless digital thermometer and I measured the temp on the subject hub and it was only 25 degrees higher that the other three. The temp reading was 140 degrees F. So for now I am not going any farther on the mystery.

 

[Tractorat]

Your welcome, it was just a thought.

The other this is though. The last time I had brakes put on my TT, one or two of the wheels got pretty hot at first. I took it back to the repair shop thinking that I had another bad magnet or something. They told me that it just takes 5-800 miles of driving to get the new shoes worn in to match everything up. I dont know for sure if he was right. But after a couple of hundred miles, the problem went away.



RRat

 

[richardcoxid]

I had a similar problem with one of my trailer brakes, IE one brake drum was HOT no matter how it was adjusted. The shop pulled the hub and drum, further examination showed the pivot point of the brake actuator arm was binding (hanging up). When the brakes the retraction springs couldn’t fully retract the shoes and it would drag.



He pulled the retraction springs, clips, shoes and the actuator arm. Everything down to the bare backing plate. Cleaned and polished all mating/mounting and pivot points. On re-assembly he used a very SMALL dab of Hi-Temp anti size lubrication on all the contact points. He said that the because of age and moisture that sometimes the actuator arm pivot point will become corroded.



After the re-assembly I took the Rv for a test drive, that brake shoe was approximately the same temp as the other three. Needless to say I went back and he did the other three. This has become a part of the annual brake inspection routine.



Hope this is what your trouble is and that it works out for you.

 

[BHoerling]

Thanks Richard. Sounds good, we will give it a try. I do the same thing on our truck brake moving parts. We have the same truck with 136K miles. All is very good.

 

[richardcoxid]

I should have added to my previous post that occasionally when on a gravel/dirt surface I will back up at about walking speed and MANUALLY apply maximum RV brake force (W/O using the TV brakes) with the brake controller. Then do the same thing going forward. I will do this for 2-3 cycles. What I am trying to do is to EXERCIZE the actuating arm/pivots to the maximum in BOTH the forward and reverse directions. Probably 99% of normal braking is in the forward direction only. I think that this will help to keep the brake assembly “free” and not binding up.