break away switch

[SRehberg]

Well I fell into the same situation I have read about before where the break away cable on a trailer (5th wheel in this case) gets snagged on something and causes the brakes to lock up. I was going around a corner when it all came to a screeching halt, the cable snagged on the hitch bed rails. I always try to route the cable so it can't snag but Murphy rerouted it. My question is the brakes on the trailer locked up then released moments later... normal? or did something open up? I would imagine some safety device would have to open the circuit to prevent damage to the brake circuit.

 

[CPG]

This is not an unusual thing to happen. When the brake away plunger is pulled out of the case, a set of contacts closes to let the trailer battery apply the brakes on the trailer. This is constant current going to the brake magnets. Its possible that a circuit breaker in the trailer or fuze was opened at this time to protect the brake valve in the truck from burning out. This is a emergency help if one drops the trailer when moving, but at the very best it would be a very "hairy" experience on the highway. If a time limit is imposed in applying and locking the trailer brakes up, I am not aware of this. Most certanily the voltage will continue to flo from the trailer battery until the circuit is broken or the contact pin is reinserted.



Chuck

 

[SRehberg]

I'm going to have to trace the wiring and see what is going on, as if it is ever needed, I want it to be functional. I noticed at the time on the brake controller, the green LED was out, but as soon as the 12V was restored, the LED was green again. There must be a circuit breaker or something to protect the wiring but it reset or blew a fuse because the little plunger was still out when it restored itself. I can't imagine a direct circuit from the battery to the brakes w/o some sort of protection.

 

[CPG]

SRehberg.



It sounds like you may have a Prodigy brake control on your rig. If true, this is proof that there is safety built in to protect the drain. The control signaled a connection to your trailer that the plug was installed and current to the trailer.

 

[SGuidry]

SRehberg,



Although you did not have a true emergency loss of your trailer, maybe I can help answer a couple of questions raised.



All trailers with brakes, whether vacuum hydraulic, air or air hydraulic, and electric trailer brakes are required to activate and hold for 15 minutes in an emergency breakaway situation. I will paste some information from The Code of Federal Regulations (CFR) that address this subject. This is from CFR under subject Transportation concerning Brakes. Title 49, volume 4 Sec. 393. 43. Breakaway and emergency braking. It is a government publication so as you can guess, it reads like Shakespeare.



Here the regulations are that your tow vehicle's brakes must not be dependent on your trailer brakes.



(a) Every motor vehicle, if used to tow a trailer equipped with

brakes, shall be equipped with means for providing that in case of

breakaway of such trailer the service brakes on the towing vehicle will

be sufficiently operative to stop the towing vehicle.



This addresses breakaway actuation and application time.



(d) Every trailer required to be equipped with brakes shall be

equipped with brakes of such character as to be applied automatically

and promptly upon breakaway from the towing vehicle, and means shall be

provided to maintain application of the brakes on the trailer in such

case for at least 15 minutes.



If you ever wondered what the smallest size a trailer can be and not be equipped with brakes, here is the answer:



(3) Any full trailer, any semitrailer, or any pole trailer having a

GVWR of 3,000 pounds or less must be equipped with brakes if the weight

of the towed vehicle resting on the towing vehicle exceeds 40 percent of

the GVWR of the towing vehicle.



Hope this helps.

Steve G.

The BrakeSmart Co.

 

[SRehberg]

Thanks for the information Steve, my trailer definetly didn't hold for 15mins. so something opened up. Now it's troubleshooting time.

 

[B.G. Smith]

?????

Do you have straight electric brakes or electric operated hydrauulic? Mine has elec. /hyd. and the instructions that came with the trailer says that if the brakes are fully applied (locked up or cought in traffic) for more than three minutes, the apply motor may burn up. bg

 

[SRehberg]

My brakes are straight electrical, that's why I'm concerned there is a problem.

 

[B.G. Smith]

Brakes

My brakes are straight electrical, that's why I'm concerned there is a problem.

Sounds like an auto reset circuit breaker. Mine has two mounted in 10 ga. wires near the battery and I suspect one of them is for the brakes. bg

 

[SRehberg]

I have to dig a little deeper into the electrical. I checked all the 12V fuses and they are all good. I didn't readily see any circuit breaker type overcurrent devices that were obvious. I have to see if there is 12V at the switch on the pin box then go from there. If there is, then there is an automatic device hiding somewhere. I was just surprised it restored itself so quickly; i. e. it let go of the brakes in less than a minute.

 

[OTRPU]

Could it just be dead??

Maybe the reason the brakes released was the battery died. I've had my batteries fail after I installed specifically to supply power for the breakaway. Most recent, my dandy Trojan, middle cell developed a leak/crack and all liquid in that cell drained out into the battery box. I noticed it when I pulled the pin from the brakeaway and got nothing. I carry two batteries just in case. Fact I carry two of bout everything, alternators, brake controllers and fan belt. DOT pulls that pin and has you try and drive away. If the brakes aren't operational they put you OOS until they are, after they write the citation. I've actually seen haulers put a battery in the trailer and NOT connect it up. I ask him what's the point? He just didn't wanna. Beats me. . . I run accross it all.



Cheers,

Steve J

 

[SRehberg]

I just bought the two batteries that are in there a couple of days before the trip. They are both a matched pair and are deep cycle 115 A. H. I tested the batteries and they are both good, so today I need to get out there and put an end to the mystery. I'll let you know what I find.



Follow up: I traced the wiring and the mfg was really good at hiding the overcurrent device. It was located under the sofa you pull out to make into a bed. Took me a little bit to find that one. It is the automatic reset kind so that explains the reset after a bit. The time it was on though as I stated above, was less than a minute. This normal?

 

[Ron Bissett]

Thirty amp braker next to the bat try or by the converter , auto reset, normal time ? when it cools down ,make sure its not over thirty amp. Use a bungee or rubber cord loop thred the brake a way line through keeping it up away from any snags. hook it on the pin box. Caution do not test the brake a way while the power connector is plugged in to the truck as it could fry the controller. Ron Bissett in Metro Louisville KY

 

[MacHaggis]

Strikes me I recollect a caution about testing the breakaway with the brakes connected to the towing vehicle, the hazard being smoking the controller if both are kisked in at the same time. So . . . if the event starts with the breakaway kicking in, then you apply some brake on the cab end so's to get a better look at what's goin' on down back . . . but you say it released. Could you have fried a wire on the trailer end that broke the circuit entirely? Any braking on the trailer now?

 

[SRehberg]

Sorry about a little slow getting back, we were gone for a few days. Now I don't know if the controller is any good or not; it didn't seem to get my attention for the rest of the trip (40mi. +/-) that something was up. At the time it happened, I was going around a corner at a slow speed, but I can't recall if the truck brakes were still being applied or not. I did notice the green light on the controller was out, but was back on when the trailer brakes reset. I'll have to reconnect to the trailer and see if things seem to work o. k. when the manual lever is moved. You have my attention about frying the controller.



I did have on my other CTD, a older style hydraulic controller that was nice to use, but the internal hydraulic piston started to ooze fluid after awhile. I guess time catches up with everything; I found another that I plan to install as it worked a lot better than this Voyager by Tekonsha that is on the truck.

 

[Eric_77]

Do you have straight electric brakes or electric operated hydrauulic? Mine has elec. /hyd. and the instructions that came with the trailer says that if the brakes are fully applied (locked up or cought in traffic) for more than three minutes, the apply motor may burn up. bg

B. G. sounds like I would take the rig back to manf. as posted by SGuidry it does not pass the federal requirements of 15 minutes.



If the circuit breakers popped after full apllication of the brakes I would think you have a worn out magnet in your brakes or an exposed wire that is shorting. When the trailer break away switch is pulled it applies 12 volts if you also apply brakes from brake controller you do not add a second 12 volts it is still just 12 volts applied to brake system.

 

[SRehberg]

The trailer brakes shouldn't pop the breaker in a full voltage condition for at least 15mins? That must mean something is shorted (does a worn out magnet do that) causing the early release? I would think the magnet windings would remain the same, just the face of the magnet is worn, unless the windings are now exposed and shorting out when they contact the drum.

 

[B.G. Smith]

???

The trailer brakes shouldn't pop the breaker in a full voltage condition for at least 15mins? That must mean something is shorted (does a worn out magnet do that) causing the early release? I would think the magnet windings would remain the same, just the face of the magnet is worn, unless the windings are now exposed and shorting out when they contact the drum.

The winding is embedded in the cast iron magnet, I suppose it is possible for the iron to wear enough for the winding to be exposed, since the breaker don't open immediately, that is probably the case. If that is the case you should be able to isolate which wheel is at fault with an ohm meter. I checked the resistance on a 4 brake unit recently and I believe the reistance was 8 ohms with all magnets connected. If you decide to check it this way you will have to isolate each magnet( disconnect it from the circuit) as they are wired paralell. you could hook up to the brake circuit and disconnect one at a time and determine which one is at fault. bg

 

[SRehberg]

Thanks for the information, I would imagine the resistance on any one magnet would be in mid teens of ohms if I read this right. If four in parallel are 8 ohms, then a single would be higher. If one is shorted, then I should read almost zero or something very low. Thanks for the heads up.

 

[Eric_77]

yes when the magnets wear out they do cause a short or if they get grease in them (they should be sealed against that though)