Pull the breakaway cable when parked?

[TxCowboy]

A buddy and I were talking this weekend while we did a little minor maintenance on my 5er. He told me that, since the 5er is parked (not connected to the tow vehicle), I should pull the breakaway cable so that the trailer brakes lock. He says he has his cable pulled all the time when he's at home or at an RV park and connected to shore power.

I would think that this is a bad idea. First off, it puts a continuous demand on the 12 volt system which could eventually damage the battery's ability to hold a charge. Secondly, I can't imagine that keeping the brakes applied is a good thing, in general, for the braking system. Anytime I disconnect the RV from the truck, both sets of wheels are chocked front and rear so keeping the RV from moving shouldn't be an issue.

What say you? Is it a good practice to pull and store the break away cable when the RV is parked, even if connected to shore power?

 

[RoadJunkie]

No, not a good idea.

 

[MTPockets]

No, not a good idea.

agree

 

[TxCowboy]

Are the reasons I gave in the second paragraph correct or are there other, more important reasons to NOT pull the break away cable?

 

[jimtoo]

You are correct, do not pull breakaway cable.

 

[BigJim45]

Bad Bad thing to do.

 

[ChangingPlaces]

Agree with every one. not a good idea.

 

[danemayer]

Setting aside the electrical issues and assumption that the brake magnets are design for continuous use, there's the question of how the electric brakes work. When the magnets are energized, as the wheel continues to rotate, a linkage pulls the shoes into contact with the drums, applying pressure to stop rotation. The wheels continue turning for a foot or so as the linkage engages the shoes. If your buddy is setting up and then pulling the breakaway cable, while the magnet is energized, the shoes aren't yet tight against the drums.

 

[jnbhobe]

All I can say is WOW !!

 

[guyc66]

A buddy and I were talking this weekend................He told me that, since the 5er is parked (not connected to the tow vehicle), I should pull the breakaway cable so that the trailer brakes lock. He says he has his cable pulled all the time when he's at home or at an RV park and connected to shore power.

I'm thinking your buddy may have recently slept in a Holiday Inn Express.

 

[mountainlovers76]

Bad idea. That will shorten the life of magnets and drain your 12v coach battery if something happens to the shore power (i.e. tripped breaker) when not being used. Also, the brakes are not "locked" when pulling the breakaway cable in a stationary position. There has to be some movement to engage the brake shoes against the drums after the cable is pulled.

 

[whp4262]

I agree with the others, pulling the breakaway cable is a bad idea. If the coach is not hooked up to shore power it will drain the coach battery in a short time and if it is hooked to shore power it's putting an un-necessary load on your converter. It will probably also shorten the life of your brake magnets considerably.

 

[porthole]

I'd be wiling to bet the first round around a campfire that your buddies breakaway switch died long ago.

The retail price for these switches is usually under $10, and over the years I have seen more then one switch that looked good, but was burned out internally. The switch is not designed to carry a 10-12 amp load for an extended period of time.

Since i didn't see it specifically mentioned as to why not; the breakaway switch is designed just for that, in the event your trailer breaks away from the tow vehicle.
The break away is electrically connected to either your trailers house battery or a small independent battery, typically a small "alarm system" type sealed wet cell 12 volt battery.

When the plunger is pulled out, the full current capacity (battery and wiring) that is available, is applied to the brake system. If the brakes are in good shape electrically, and the wiring is up to the task, then approximately 3-4 amps per brake assembly is being drawn when full power is supplied. But no brake action is being applied because of the way the system works.

10-12 amps for an extended period of time will "test" your wires (usually just barely adequate for the application) and will overheat the break away switch and cause it to fail.
I recommend to all campers that travel a lot, buy an extra switch, they are cheap and can fail at any time. It is one of the few spare parts I carry.

BTW, if you have "electrically activated hydraulic disc brakes" as many of us have, pull that switch and leave it and I'm sure your camp neighbors will let you know something needs to be done. The pump running and putting out 1600 PSI will be quite noticeable.

Pulling the plug on the disc brakes will activate the hydraulic pump and supply full braking power to the disc brakes, locking the wheels.

It is recommended with electric over hydraulic disc brakes that if you are stopped for more then a few minutes, such as at a railroad crossing, that you put your truck into park and take your foot off the brakes. Whenever your foot is on the brake pedal, the hydraulic pump is running.

Somewhere on this site I posed a good animated graphic of how the drum brakes work.

 

[TxCowboy]

Good comments, all. Kudos to Porthole for his detailed explanation.

 

[jmgratz]

I am almost willing to bet you that your friend is messing with you. I don't know any RVers who have any knowledge of RVs who would pull their brake switch while camping. If you ever looked in your owners manual it even states not to do that and why. Tell your friend that was a good joke but you didn't fall for it.

 

[priorguy]

I am almost willing to bet you that your friend is messing with you. I don't know any RVers who have any knowledge of RVs who would pull their brake switch while camping. If you ever looked in your owners manual it even states not to do that and why. Tell your friend that was a good joke but you didn't fall for it.

I remember that from my Coleman pop up camper manual. I believe it stated that the braking components could overheat and that if the battery or fuse went the trailer could potentially roll away. Wheel chocks or similar devices are the only way to go.


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