Interesting Brake Problem

[Bob Landry]

The last time I used my trailer, I noticed that my trailer brakes locked up. It happened twice that I recall and it was at a very slow speed such as coming to a stop. I wasn't sure if it was all or one of the brakes that locked.
Today, I went out to move the trailer so I could open a slide out. I saw four skid marks where the trailer had been parked, so that told me that the lockup was on all four wheels and in that particular time, it was as I was pulling out of my storage space. That tells me that the brakes had to get 12V from somewhere and it wasn't just a tight brake shoe locking up.
Now, where does it get 12V? Only two places that I can think of, either the break-away switch or from the brake controller on the truck.

Having said that, has anyone ever heard of a break-away switch going bad and the contacts shorting internally? I'm going out tomorrow to check the switch and make sure everything looks correct on the switch. I did have to replace the 7-pin plug back in October, so I need to make sure no strands broke loose in the plug and are shorting out against another wire or something. Am I missing anything else? I want to make sure I cover everything before I go to the Ford dealer and try to convince them I have a bad controller.

[DJ85]

Someone correct me if I am wrong but if it was breakaway problem wouldn't the brakes be applying all the time? What is your brake setting on the brake control? I do know if it rains or there is heavy moisture in the air the drums develop surface rust and this will cause the wheels to lock up. After a couple application everything returns to normal.. I get a loud screeching noise from mine last year before I put it in storage. Figured I would do a wet bolt upgrade and repack the bearing and see whats going on. I another note if you over grease the breaing and the seal starts leaking grease on the shoes will either cause them to not hold or lock up as well. Just my swag!!!!!

[Bob Landry]

Originally Posted by DJ85

Someone correct me if I am wrong but if it was breakaway problem wouldn't the brakes be applying all the time? What is your brake setting on the brake control? I do know if it rains or there is heavy moisture in the air the drums develop surface rust and this will cause the wheels to lock up. After a couple application everything returns to normal.. I get a loud screeching noise from mine last year before I put it in storage. Figured I would do a wet bolt upgrade and repack the bearing and see whats going on. I another note if you over grease the breaing and the seal starts leaking grease on the shoes will either cause them to not hold or lock up as well. Just my swag!!!!!

The switch would have to be intermittent, maybe affected by vibration of some type. Otherwise, yes, the brakes would be actuated all the time. I can't buy that residual rust would lock brakes up, otherwise there would be a lot of brake related accidents on the roads. Plus, all four skid marks are identical so the probability of all four hubs rusting and locking up for identical periods of time is zero.

[ctpd814]

I would be looking in the 7 pin connection by the way you are describing it. It sounds as though the 12 volt charging wire may be bleeding into the brake wire occasionally.

[DJ85]

The rust things only happens on the first couple of brake application. It's more pronounced on drum brakes.

[Bob Landry]

Originally Posted by ctpd814

I would be looking in the 7 pin connection by the way you are describing it. It sounds as though the 12 volt charging wire may be bleeding into the brake wire occasionally.

That would be a strand breaking loose and touching something that it shouldn't. I'm going to pull the plug apart today and look at it. That's pretty unlikely though, because the plug that I put on actually had little ridges/barriers molded into the plug between the connectors. It's still worth a look.