Breakaway Switch Pin left out!

[rmroy]

Yet another pilot error.

I pulled out the Breakaway Switch Pin to make sure it was functioning. It took much a harder tug than I was expecting but it finally came out cleanly. Unfortunately, I got distracted by something, (happens a lot lately!) and didn't remember until the next day, about 18 hours later to replace it. What concerns me is the caution in the manual (Classic 2018) that says "Allow no more than 20-30 seconds pin separation as damage to the brake magnets may occur."

My concern is that damage potential, the warning seems a bit extreme. Do I need to worry, can I easily test for this damage?

Thanks,
Roland

[OTRA15]

Above my pay grade, but . . . here goes . . . IMO and FWIW . . .

Are your trailer batteries OK? Check voltage on your panel. If they are flooded cell, is the water level alright? [use caution -- gloves, safety goggles, etc. per manual] Maybe AGM's?

Is it easy to hook up to tow vehicle, and manually check if the trailer's brakes work OK, at least in your driveway or parking lot of the storage area, at a low speed?

The new search function in the blue box above works great, and here are some results to check:
"breakaway pin out battery damage" -- https://www.google.com/search?q=brea...com&gws_rd=ssl

Possible threads:
http://www.airforums.com/forums/f439...able-7308.html
http://www.airforums.com/forums/f439...tch-22373.html

Good luck,

Peter

[AtomicNo13]

Brakes work= no damage
Brakes no work= damage

Is your battery flat?

[Action]

Doing that drains the battery.

>>>>>>>>>>>>>>>Action

[rmroy]

Thanks, what I haven't mentioned is that we were plugged into shore power the whole time. So there was no drain on the battery (AGM). The converter fan was continuously running I had no idea why, I know now. My concern is the breaks being engaged for so long. I will check out the threads suggested.

[hoagy_007]

I have a 2018 30' FC Bunk and when we got it we were newbies. I had left the breakaway pin out for a week! When I came back the batteries were dead (gave me an excuse to upgrade to AGM's). There was no damage to the brakes, they have been working fine since, and this happened about 2 months ago. We've been on 5 trips since then with no issue.

[Action]

Originally Posted by rmroy

Thanks, what I haven't mentioned is that we were plugged into shore power the whole time. So there was no drain on the battery (AGM). The converter fan was continuously running I had no idea why, I know now. My concern is the breaks being engaged for so long. I will check out the threads suggested.

Should be no other damage because the wheels were not moving. Big draw of power with not much done. The current will go through the brake magnets. The magnets will grab the brake drums verticle surface. Since the drum was not moving not much else happened.

>>>>>>>>>>Action

[rmroy]

Awesome, that's what I had hoped to hear, but then ... on the Forum I found this, and got very concerned:

" Originally Posted by Inland RV Center,
If a trailer is plugged into city power, and the breakaway switch is pulled, it's been known to easily destroy the magnets, warp the drums, and to also discolor the bearings and spindles, to the extent that continued useage, would be a big gamble.


Without being plugged into city power, there can be enough wattage in a good battery/batteries, to absolutely burn up the magnets, before the voltage disappeared.

It's a very good idea, to pull the drums for a close visual inspection.

Travel trailer braking, should never be guessed at.

Andy "

I certainly hope this is not an issue.

[Action]

A bit over dramatic post in my opinion based on the unknown.

The magnets are rather high in mass. Not sure how they would be destroyed by passing a current through them. As far a warping drums, discoloring bearings and spindles that is only posible IF the drums are spinning.


Just know that metal scrap yards have a huge magnets that can pick up cars! The current that passes through those magnets is many times greater than what can be generated by your 12 volt RV battery. And those magnets do not warp.

Drama! It makes for a fun read. Just not based in reality.

>>>>>>>>>>>>Action

[worden]

Assuming a current draw of 4 amps per magnet coil you would be putting ~50 watts into each brake system. This does not sound like enough heat to do damage. Imagine sticking a 50 watt light bulb into the brake area. There is a lot of metal present to move the heat away and therefore avoid any hot spot. A more likely failure is a hot spot in the wiring due to a poor electrical connection. If one or more of the brakes do not function after this event I would look for a burned electrical connection.

[rmroy]

Thanks to all, We are total newbies, so these mistakes do cause some anxiety. Good to hear that we likely did not do any damage.

[Bob662]

Hook up trailer. Go for a drive. Accelerate to about 20 MPH. Manually apply trailer brakes (not the foot brake). If trailer slows, trailer brakes are OK. If not, go to the next step -- remove wheels then the hubs. Inspect for overheating. Replace trailer brakes. They're not very expensive.

[uncle_bob]

Hi

Ok, the way magnets die is not by melting the brakes or by causing the tires to explode. They also do not teleport your trailer to an alternate universe. What happens is the coil heats up enough to break the wire in the coil. When that happens, no more current. No more current means no more braking from that magnet.

Testing requires a high tech set of gear and a very complex test procedure ....

1) Apply brakes
2) Listen for magnets pulling in brake shoes ( the click noise)
3) un-apply brakes
4) should go click again

Yes, that's a real high tech process

You can indeed start un-wiring things and checking them with an ohm meter. You can also feed the brakes with a 12V source and look at the current. All of this requires a knowledge of how much current *your* brakes should pull. I'm not going to guess at that.

One additional hint - if they go click when the brake is applied, but don't go click when it's un-applied (or it takes 10 to 20 seconds) .... errr .... schedule an appointment to get them checked. That's one of the signs your brakes have a broken spring on the adjuster and are eating themselves internally .....

Bob

[Al and Missy]

Per the Dexter manual, the brakes should draw about 3A each.


Several things could happen with long term current through the magnets:
1. The magnets could become partially permanently magnetized. If this happens they may not fully release.
2. The magnets are made by winding many turns of relatively small wire around an iron core. Heat can damage the insulation on the wire coiled around the core. If this happens, the one part of the coil could be shorted out, current will increase and braking force will decrease, the amount depending on how much of the coil is shorted out.
3. If the wire is small enough, and the current high enough, the wire can fail. If this happens both the current and the braking force will go to zero.
4. Nothing - the brakes will be fine.


The best way is to test the brakes is by driving, but it helps to have a baseline of what the brakes did when new. Drive about 20 mph on a paved surface in a remote area. Fully actuate the brakes using only the lever on the brake control. For smaller trailers, you should be able to increase the gain on the controller until the brakes lock, but results are mixed on larger, heavier trailers. Some can get theirs to lock; I couldn't. I ended up replacing my drum brakes with discs because I was concerned i wasn't getting optimum braking power. Locking is best observed by an assistant on the side of the road where you will apply the brakes, first on one side of the trailer and then on the other. Ideally all brakes will lock at the nearly the same gain setting. If they do, reduce the gain until they are at the threshold of locking but do not lock and you are done. If you can't get them to lock, or if some do and some don't, you may have some removal, inspection and testing to do (See above about larger trailers).

If repairs are needed Dexter recommends anything you do, like replace a magnet, drum or shoes, be done on both sides of the axle.


Al

[uncle_bob]

Originally Posted by Al and Missy

Per the Dexter manual, the brakes should draw about 3A each.


Several things could happen with long term current through the magnets:
1. The magnets could become partially permanently magnetized. If this happens they may not fully release.
2. The magnets are made by winding many turns of relatively small wire around an iron core. Heat can damage the insulation on the wire coiled around the core. If this happens, the one part of the coil could be shorted out, current will increase and braking force will decrease, the amount depending on how much of the coil is shorted out.
3. If the wire is small enough, and the current high enough, the wire can fail. If this happens both the current and the braking force will go to zero.
4. Nothing - the brakes will be fine.


The best way is to test the brakes is by driving, but it helps to have a baseline of what the brakes did when new. Drive about 20 mph on a paved surface in a remote area. Fully actuate the brakes using only the lever on the brake control. For smaller trailers, you should be able to increase the gain on the controller until the brakes lock, but results are mixed on larger, heavier trailers. Some can get theirs to lock; I couldn't. I ended up replacing my drum brakes with discs because I was concerned i wasn't getting optimum braking power. Locking is best observed by an assistant on the side of the road where you will apply the brakes, first on one side of the trailer and then on the other. Ideally all brakes will lock at the nearly the same gain setting. If they do, reduce the gain until they are at the threshold of locking but do not lock and you are done. If you can't get them to lock, or if some do and some don't, you may have some removal, inspection and testing to do (See above about larger trailers).

If repairs are needed Dexter recommends anything you do, like replace a magnet, drum or shoes, be done on both sides of the axle.


Al

Hi

Ok, if you suspect the cores have become "permanently magnetized" ( = no click) put -12 on the brakes rather than +12. Keep it there for 5 or 10 minutes ... very likely the problem is solved.

If you suspect a short, then go to the "measure the current" approach. Given the heat in a brake system, the insulation on those cores is going to be mighty high temperature stuff..... Lead foot Bob going down a long grade can get brake drums smoking .... The cores are right there by all the heat.

If the brakes each pull 3A, you are at 36W per coil. Yes, they will get quite warm running at that sort of power for a day or two. The concern about doing damage is valid. There are multiple coil designs out there. One might be more rugged that the other ( = yours are fine after 18 hours / mine are toast).

Lots of variables, no absolute answers.

Bob

[rmroy]

Travelled yesterday, did some moving break tests, they seem to work fine. Thanks again for all the support.