Electric Brakes Not Releasing

manyman297

2021 400. Just repacked the bearings this spring and finally got it out on the road this weekend. Things were fine until I was at a stop light and squeezed the brake controller manual lever just to test it. Upon letting off the truck’s brakes the vehicle didn’t creep forward as it always does when I release the brakes. 

As I accelerated I could feel resistance. Pulled over, disconnected the 7-pin thinking it was an electrical issue. Plugged it back in and still felt it dragging. Finally I decided to back up a few feet….this did the trick and all was well. Several miles down the road I could tell the brakes were grabbing again as I was going downhill but losing speed when I let off the gas. 

Pulled out the temp gun and the passenger side drum was 210 and the driver side was 144. So something isn’t releasing and it doesn’t seem to be electrical in nature. Anybody else have an issue like this? I read that maybe the return springs in the drum mechanism could be the culprit?

Bayliss

@manyman297, I do not have a specific answer, but you indicated that it does not seem to be an electrical issue, so I am just throwing out the below question as a possibility (which would be an electrical issue.)

You did not mention it in your post, but have you checked to confirm that the emergency breakaway/brakes controller pin is properly secured?  If the switch is activated (pin pulled out), that would make an electrical connection between the trailer battery and the electric brakes.  (Other parts of your post tend to be inconsistent with that possibility, such as backing up and the brakes apparently disengaging for a period of time, so this is a "just in case" response.)

pthomas745

Frayed brake wire?  

https://tab-rv.vanillacommunity.com/discussion/13863/frayed-brake-wire-on-2021-400-bd

Grumpy_G

@Bayliss already suggested an easy thing to check. Otherwise I'd think the brakes are adjusted too tight. Drum brakes are typically "self-energizing" (actually self-servo) meaning the front (leading) shoe pushes the rear shoe against the drum. The front shoe doesn't require a lot of pressure against the drum to create a lot higher braking force at the rear shoe. 

Did you change the adjustment of the brakes to remove and reinstall the brake drums ? The brake shoes are sort of floating so you might have to remove the drums again and check if anything is askew. 

manyman297

Bayliss said:

@manyman297, I do not have a specific answer, but you indicated that it does not seem to be an electrical issue, so I am just throwing out the below question as a possibility (which would be an electrical issue.)

You did not mention it in your post, but have you checked to confirm that the emergency breakaway/brakes controller pin is properly secured?  If the switch is activated (pin pulled out), that would make an electrical connection between the trailer battery and the electric brakes.  (Other parts of your post tend to be inconsistent with that possibility, such as backing up and the brakes apparently disengaging for a period of time, so this is a "just in case" response.)

Yeah, I checked the breakaway cable but I don’t believe that to be the cause. Backing up worked that one time. I tried it again later in the trip and it didn’t work. 

manyman297

pthomas745 said:

Frayed brake wire?  

https://tab-rv.vanillacommunity.com/discussion/13863/frayed-brake-wire-on-2021-400-bd

Funny you post that since it’s my post 

After that incident I religiously check those wires. I also think this issue is mechanical and not related to any electrical problems. 

manyman297

Grumpy_G said:

@Bayliss already suggested an easy thing to check. Otherwise I'd think the brakes are adjusted too tight. Drum brakes are typically "self-energizing" (actually self-servo) meaning the front (leading) shoe pushes the rear shoe against the drum. The front shoe doesn't require a lot of pressure against the drum to create a lot higher braking force at the rear shoe. 

Did you change the adjustment of the brakes to remove and reinstall the brake drums ? The brake shoes are sort of floating so you might have to remove the drums again and check if anything is askew. 

I did notice the passenger hub was much harder to break free when packing the bearings. Almost like the shoes were slightly engaged still. I don’t recall them being like this the last time I repacked but that was some time ago. 

If they were too tight I’d constantly be feeling this drag and my brakes would have probably overheated at this point. Plus backing up somehow released the shoes in some way. 

What’s odd is that I test drove the camper around town and on the highway last week and everything was fine. Temp on both hubs was within 10% of each other. 

I need to check the adjustment on the passenger side when I get a chance. I need to figure this out before our next trip in a few weeks. 

pthomas745

@manyman297 Yes, funny how those things work sometimes.

The "frayed brake wire" info you gave has helped plenty of other owners with that same issue.

Horigan

I would pull the drum off and inspect the mechanism looking for areas that may be corroded or sticking. If this is new behavior, I wouldn’t address by loosening the shoes.