Breakaway Cable Length - What do you do?

[uncle_bob]

Hi

It the case that you pull the breakaway switch, you are putting straight 12V from the trailer battery full on to the brakes. That's a very different condition than what your brake controller may or may not do. The only way to see what happens with the switch is to use it. The wire lengths are different, the battery is different, the outcome probably will be different.

If you don't have anti-skid brakes, then you can loose directional control with a full wheel lockup. That's just the way it works. The magic switch is not very smart. It just puts on full brakes and that's it. The trailer then tries to stop both it's self and your 7,000 lb tow vehicle. Yes, eventually you will get your foot onto the TV brakes. No matter how fast you are, that will take a *long* time relative to loosing control.

Toss in fun stuff like: Tries on the trailer that may not match. Weight distribution (left to right) that may not be ideal. Bits and pieces of your anti sway hitch that may or may not still be there. There are lots of inputs to this ....

Bob

[Boxite]

Originally Posted by uncle_bob

Hi

It the case that you pull the breakaway switch, you are putting straight 12V from the trailer battery full on to the brakes. That's a very different condition than what your brake controller may or may not do. The only way to see what happens with the switch is to use it. The wire lengths are different, the battery is different, the outcome probably will be different.

If you don't have anti-skid brakes, then you can loose directional control with a full wheel lockup. That's just the way it works. The magic switch is not very smart. It just puts on full brakes and that's it. The trailer then tries to stop both it's self and your 7,000 lb tow vehicle. Yes, eventually you will get your foot onto the TV brakes. No matter how fast you are, that will take a *long* time relative to loosing control.

Toss in fun stuff like: Tries on the trailer that may not match. Weight distribution (left to right) that may not be ideal. Bits and pieces of your anti sway hitch that may or may not still be there. There are lots of inputs to this ....

Bob

Unlike what was suggested by another, you don't "push my button", and I hope I didn't hurt any feelings... but I get the impression that in an effort to be conversational, you are postulating on your desktop ...?? I believe all that does is contribute confusion to the discussion.

The full-blown voltage applied by the breakaway switch is no different than the full-blown voltage applied by the brake controller when the trailer brakes were first set-up in accordance with most controller-instructions. (In fact, it may actually be less powerful because when applied by the TV brake controller the TV electrical system, via the alternator charging circuit, is supplying approximately 14 volts or more... not the less-than-14 expected from the trailer battery.)

Most brake controllers instruct the operator to apply full brake-controller effort to the point of trailer wheel lock-up...without actually locking the wheels. Hopefully this will be accomplished on the type surfaces expected during most operations. (Although my personal preference is to adjust only just to the point of wheel lock up on a slightly loose surface such as a hard-packed dirt road (to obtain maximum trailer braking without actual wheel lockup.)

Yes, if on a slippery/wet surface the trailer wheels may lock up...but that is also when a smart driver will be travelling at a more reasonable speed. (If still driving hell-for-leather.... nothing is going to go well..... you can't fix stoopid.)

As for the poster who suggests that drum brakes are more likely than disc brakes to lock up.... that is exactly the reverse from facts. All braking systems (in the vehicles we're discussing) convert kinetic energy to heat energy using friction. Drums will e-x-p-a-n-d when heated by brake application and as the braking-experience continues, the braking will become LESS effective... therefore retreat from any tendency to lock up. DISCs will also expand... thereby affording g-r-e-a-t-e-r contact between the disc and the friction-pads and consequently INCREASING braking effort toward a lockup condition. That very difference is why disc brake systems have largely replaced drum brakes in most vehicles.... to avoid brake-fade.

Discs also have an advantage of centrifugal force which results in a self-cleaning/expelling action after submergence in water/snow/etc., while drum brakes retained the contaminate for longer periods (and also have more complicated/delicate operating mechanisms.)

[uncle_bob]

Originally Posted by Boxite

......

Most brake controllers instruct the operator to apply full brake-controller effort to the point of trailer wheel lock-up...without actually locking the wheels. .....

Hi

That's the key point. If *you* still have control of the brakes, you have some chance of accomplishing it. Once the brake away switch cuts in, you no longer have control over the trailer brakes.

Brake controllers do all sorts of interesting things to limit the braking force. The brake away is just a simple switch through very short wires. What you observe with your controller may (or may not) be what you get with the switch.

Bob

[Boxite]

Originally Posted by uncle_bob

..Once the brake away switch cuts in, you no longer have control over the trailer brakes. ...
Bob

My friend... once the conditions are met to activate the breakaway switch... you no longer have control over the TRAILER. It will start swaying around on the chains until it possibly flips the trailer and YOU...and maybe kill someone as well.

Bottom line: Look at the videos posted by another. If the trailer comes off the ball... you want the trailer to apply the trailer brakes!

[GCinSC2]

Originally Posted by KK4YZ

This all boils down to the question of whether the trailer brakes can actually lock up the wheels on dry pavement at highway speeds... let's say 65MPH.

Does anyone have any knowledge of this?

Nope, no knowledge. But I bet my EOH at full system breakaway pressure will if any brakes can.

But the goal should be to never have to test this assumption and not even sure if a full panic skid stop would be ideal either.

Check your hitches, chains, umbilical, breakaway switch and cable, receiver, coupler, ball and follow a check double check procedure.

See ya at the next campfire.

[rodsterinfl]

This is an excellent discussion and one certainly important enough to debate. I believe the issue is that a brake lock-up is bad, yes; however, it is the safest way to deal with an uncoupled situation. A driver would be only reactionary in such a situation whereas the switch, by actively engaging at the "time of disconnect", begins stopping the trailer and tow vehicle. The tow vehicle's weight would drag the trailer in the direction of travel so it would be safer than allowing the trailer to slam against the tow vehicle while moving side to side and using the truck brakes. Again, it is a matter of "bad situation" and the switch is, in my opinion that safest way to get stopped and out of danger as quickly as possible. My motivation for posting was due to a realization via the videos and to bring it to the attention of others. I certainly did not have mine set up to disconnect if uncoupled as the standard 4" cable is too long, especially when looking at the chains extended. Safe travels.

[Boxite]

A really simple test would be to hook the trailer up on the pavement/parking-lot/etc and without connecting the 7-way umbilical... pull the breakaway switch and try to drag the trailer around the parking lot. If your tires are locked up at that point...they will likely lock up on the highway as well (although that it not a guarantee as the wheels will have already been in-motion with momentum.) But it'll give you an idea.

My trailer does NOT lock up the wheels on dry pavement. They only apply a firm drag on the TV, however even if they locked up... I'd want the trailer's brakes firmly applied in event of a disconnect.

[rodsterinfl]

OK, guess what? I just returned from Helen, GA after hurricane Irma. On my way home, my brake controller in the truck burned up. Immediately my trailer brakes seized while driving in the mountains (I had just left Top of Georgia park). The trailer dragged the truck to a complete stop from about 40mph. It was quick. The Ford dealer said that it was just a random brake controller failure. I am now wondering about some kind of power backfeed or something from the brakeaway. They said not but...

[Dan and Liz]

About as long as the umbilical, so the breakaway activates if you lose the ability to modulate the trailer brakes (but not before).

[uncle_bob]

Originally Posted by rodsterinfl

OK, guess what? I just returned from Helen, GA after hurricane Irma. On my way home, my brake controller in the truck burned up. Immediately my trailer brakes seized while driving in the mountains (I had just left Top of Georgia park). The trailer dragged the truck to a complete stop from about 40mph. It was quick. The Ford dealer said that it was just a random brake controller failure. I am now wondering about some kind of power backfeed or something from the brakeaway. They said not but...

Hi

You could check the breakaway. I believe you will find that it's a really simple switch. It just dumps the battery on the brake line. Nothing is disconnected from the 7 pin when this happens. That's true in all RV's that I've seen, it's not unique to AS. If the Ford controller dies when this happens, I'd expect to see them dying left and right ....

If you wanted to eliminate the chance of back feed, watch your hookup / tear down process. When hooking up, plug in the 7 pin after you have the disconnect switch hooked to the TV. When unhooking, unplug the 7 pin before you take the breakaway off the TV.

Since it's just a cheap diode to protect the controller, I'd bet they didn't cost reduce the protection out of the controller. I doubt it costs more than one cent in the volumes they run ....

Bob

[Farmer Dan]

Rodster, I've had two brake control modules fail on my 2015 F150 SCrew. One while on the road and the other in my driveway. The local Ford dealer tells me the modules have been redesigned. I've got nearly 2,000 mi on the replacement with no troubles.

Dan

[rodsterinfl]

I hope so. It was one scary experience. First, the smoke started rising from the dash and I got a brake failure message. At first I thought it was the truck and I was freaked. I do not know if you have been to Helen, GA but the ride from the Airstream park to town is downhill mostly and curvy. The whole place is hilly and curvy. Then the brakes locked and abruptly stopped the truck in a bad place. I hope I got a redesigned one.

[DreamStreamr]

Rodster,
I think your recent controller failure is worse than not having the brakes work, something we had on our maiden voyage a long time ago. We were able to get truck and trailer pulled over to the side on that downhill. Front disc brakes were smoking like crazy, smoke pouring out from wheel wells. But we had some control and the truck was bigger than the trailer, thankfully.

Glad you made it through your controller failure okay and yeah, hope they got you a good one now. I'd wondered about having built-in brake controller (ours doesn't) but yours is the first I've heard to fail.

Good luck and thanks for sharing what happened.

[rodsterinfl]

More info...

The Ford dealer checked my truck using a trailer of their own. It did the same thing- burned up a controller. Then, to double check, my father and I did a break away test with my trailer- all fine, no problems there. The break away did not activate during my drive and, during the test, did what it was supposed to do. That leaves the truck at fault with these two tests.

What we found out was that Ford has REDESIGNED the break controller 3X since 2015. The part # for the latest model is GL3Z2C006CB.

From this experience I can say that the trailer will stop the truck and safely. It is just that depending on the road type you are on, it can have a profound impact on your nervous system. Curved hilly roads heighten the experience!

[GCinSC2]

Ridsterinfl,

Good luck be careful and hopefully a successful outcome. SOON!

Gary

[GCinSC2]

Duplicated deleted

[KK4YZ]

Originally Posted by rodsterinfl

I hope so. It was one scary experience. First, the smoke started rising from the dash and I got a brake failure message. At first I thought it was the truck and I was freaked. I do not know if you have been to Helen, GA but the ride from the Airstream park to town is downhill mostly and curvy. The whole place is hilly and curvy. Then the brakes locked and abruptly stopped the truck in a bad place. I hope I got a redesigned one.

Rodsterinfl:
I'm very familiar with that stretch of road. I drive by the Top of GA airstream park on the way to work.
That must have been quite an adventure. Glad nobody was hurt. Than can easily happen there.

[rodsterinfl]

UPDATE

I have learned more on the Ford Brake controller on 2015 and newer F150s.

There are now seven different redesigns. The newest is not the one I was given and posted earlier. It is this one:

JL3Z19H332AA

this supersedes all previous six versions - FL3Z2C006AA, FL3Z2C006AB, FL3Z19H332AB, FL3Z19H332AA, GL322C006-CA, GL322C006-CB