Trailer brakes "bind" in traffic...brake controller "feedback"???

   / Trailer brakes "bind" in traffic...brake controller "feedback"??? #1  

KeithInSpace

Veteran Member
Joined
May 19, 2006
Messages
1,570
Location
Fred'burg, Virginia
Tractor
Kubota BX2230
Not sure what causes it. Only happens when the trailer is loaded. Generally only happens with the brakes get hot.

Basically, I'm coming up on a light and I hit my brakes like normal. Everything is going OK, but when I slow down a bit, the trailer feels like it starts grabbing more and more until I barely have any pressure on the truck's brake pedal and the trailer is slowing me down.

It seems like the inertial sensor in the controller gets into a type of "feedback loop" where it reads the trailer slowing the truck down as MORE brake pedal pressure, so it applies more pressure to the brake, which it reads as more pedal pressure...so on and so forth.

Does this happen to everyone? Do I have too much brake dialed in?

I'm running a Tekonsha P3 on an Expedition. I have a 10,000# dual axle dual brake trailer. This is most noticable (or most disturbing) when I have at least 3,000# of stuff in the trailer.

I'm able to modulate the rig...it isn't unsafe. Just figured I'd ask if it is normal. I have never driven an electric brake trailer before my ownership of this rig.
 
   / Trailer brakes "bind" in traffic...brake controller "feedback"??? #2  
Re: Trailer brakes "bind" in traffic...brake controller "feedback"???

Start from scratch and level the sensor and set the power.

Then Jack up the trailer and adjust the brakes. You did know that the trailer brakes are MANUALLY adjusted, unlike car/truck brakes that self adjust to account for wear? (many people don't know this, the trailer seller should go over it but....)

Still not fixed? Take off the wheels and make sure the magnets can move freely and the drums are true circles with no nasty rust.

jb
 
   / Trailer brakes "bind" in traffic...brake controller "feedback"??? #3  
Re: Trailer brakes "bind" in traffic...brake controller "feedback"???

Keith I am not familiar with the P3 but I am thinking about getting one. The last brake controller I had you could set the amount of current going to the brakes will the P3 let you do that ?
 
   / Trailer brakes "bind" in traffic...brake controller "feedback"??? #4  
Re: Trailer brakes "bind" in traffic...brake controller "feedback"???

KeithInSpace said:
Do I have too much brake dialed in?
Or maybe drop the level of aggressiveness a little.
 
   / Trailer brakes "bind" in traffic...brake controller "feedback"??? #5  
Re: Trailer brakes "bind" in traffic...brake controller "feedback"???

Like John was saying...

Does your trailer sit idle for extended periods of time? A little rust can make drums awfully sticky... mine sat idle for 5 months, then this spring a buddy borrowed it & ripped the right side wiring loose... (was testing & noticed only one side locked up:()

Anyway, after rewiring, still nothing, pulled the hub apart and rewired it, cleaned it up, sprayed down everything "non-braking" with WD-40 and now it is working better than the other side... now I've got to pull that side apart & do the same.

We always expect that trailer we don't use much is going to just keep right on working... disuse is right up there with misuse for stuff going south on you though...

Good luck with it
 
   / Trailer brakes "bind" in traffic...brake controller "feedback"??? #6  
Re: Trailer brakes "bind" in traffic...brake controller "feedback"???

Check the shoe adjustment on the trailer, if the shoes are way out of adjustment they can go to dragging with little voltage applied.
Also check to make sure there is no grease on the shoes from a bad seal, that also can cause them to grab even if they are adjusted correctly.
 
   / Trailer brakes "bind" in traffic...brake controller "feedback"???
  • Thread Starter
#7  
Re: Trailer brakes "bind" in traffic...brake controller "feedback"???

gemini5362 said:
...will the P3 let you do that ?
Yes, infinitely. Also has 4 levels of "boost" to alter how much the trailer "grabs" at first application of the brakes.

Works quite well. Can't say that this issue I'm having wouldn't be the case for any controller, so I haven't faulted the P3 yet.
 
   / Trailer brakes "bind" in traffic...brake controller "feedback"??? #8  
Re: Trailer brakes "bind" in traffic...brake controller "feedback"???

john_bud said:
Start from scratch and level the sensor and set the power.

Then Jack up the trailer and adjust the brakes. You did know that the trailer brakes are MANUALLY adjusted, unlike car/truck brakes that self adjust to account for wear? (many people don't know this, the trailer seller should go over it but....)

Still not fixed? Take off the wheels and make sure the magnets can move freely and the drums are true circles with no nasty rust.

jb

John I noticed you said to level the sensor. Are you talking about the sensor in the P3. According to the literature that is one of the big selling points of the p3 is that it can be mounted in almost any position. That is one of the reasons I am thinking about getting one.
 
   / Trailer brakes "bind" in traffic...brake controller "feedback"??? #9  
Re: Trailer brakes "bind" in traffic...brake controller "feedback"???

I'm agreeing with some others that you need to check for brake shoe contamination. Sure sounds like some grease got on the shoe materials. It will lock up a brake until the pressure is reversed; stop and slight roll backwards in sever cases.
 
 
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