Hot Hubs/Brake Controller

[deadeyenevermisses]

My cousin, while taking his SOB in for bearing repack, discovered both hubs on one side of his RV running about 30 degrees hotter (IR Scanner). in addition he noticed his brake controller was unusually hot. I told him I'd submit his problem to this group of experts i know........

[noneck]

Right...first pass is that the Brake drag, if controller is warm then sounds like a wiring issue causing the circuit to be active? Odd that he did not note his controller showing any current output? So...does he lay his foot on the brake pedal? Controller will apply some current when it detects a "brake light" circuit activation....amount of current typically is dependent on the inertia pendulum in the controller. Difference side to side could be a brake adjustment so drag on one side but not on other due to low current application? Hard to say its just plain brake drag as controller is hot...

[MacDR50]

I am with Noneck. Sounds like a low, probably intermittent, current as the result of the brake light circuit activation of the controller. A simple check would be to apply the brake slowly a few times after dark or in a dark garage and then get out and check the brake lights. If he detects a slight glow the brake light circuit is not de-energizing. Since you didn't mention the year and make of truck this may be a sticky brake light switch or a bad pressure detector. He can also check for a voltage on the pin on his controller that is connected to the trucks brake light circuit. The pin should be identified in the controller's installation instructions which are usually available on the manufacturers web site. If he is a two foot driver then he needs to break the habit. There is a remote possibility he is getting a current bleed from the 12v pin in the trailer connector. Water in the connector can cause this or some conductive debris. A check with a flashlight of both the truck side a and trailer side connectors may be in order. Hope this helps.

[deadeyenevermisses]

Thanks to all of you for your input. I knew he wasn't a "left footer" like I am so I dismissed that in my own sleuthing. He borrowed a controller and harness from a similar vintage and make (Ford) of truck from work and voila! 89 degrees on all four axles upon towing to the dealer. Dealer said they'd check the bearing preload anyway. I don't think his controller has the trick display like my Prodigy has which would have told him there was a current transfer going on, buthen it could be an internal short as well. THAT'S why I'm a Bow-Tie man.......

[deadeyenevermisses]

The plot thickens. He got a new controller and harness from the dealer, hooked it up and towed the trailer about three miles........hot hubs again.................

[jimcol]

Very confusing. Can't wait to hear the solution. Inquirying minds want to know.

[Art-n-Marge]

Maybe it's the wheel bearings on that side? Or maybe adjust all four brakes to see how well they are doing? Or maybe the problem could be the cooler side in that they are not working and the hot side is doing all the work. 89 degrees doesn't not seem hot enough for a heavy trailer being stopped but I don't know what it should be or how much stopping you are doing.

I wasn't going to comment because when I had a discrete brake controller it would get very warm when I was driving but I don't know if that translates to abnormal or normal. I didn't worry about it because my braking system seemed to be working.

I am commenting now, because I can add some experiences I have had over the years (brakes out of adjustment, wheel bearings needed maintenance or a questionable brake controller) in hopes of helping with ideas.

Maybe it's time to mention the SOB information. See if you can find internet information on other RV forums.

It really sounds like an IR Temp tester is really getting important. There are so many things to measure now as preventative maintenance and waiting until there is a problem will create some confusion. And the devices are only around $40, right?

Good luck debugging this.

[rames14]

It sure sounds like he found the problem. Swapped out the controller and the problem went away. Now, if he puts the controller back in and the problem comes back, he will know for sure. A problem like this should be able to be turned on and off to really know you have found the problem.

[deadeyenevermisses]

Thanks everybody so much!! Actually, I told him to swap the new Ford controller/harness that didn't work with his work buddy who's set up did work........time is short, he leaves on holidays Friday.