# Kadee couplers



## Fred (Jan 2, 2008)

I use the KD 831's and at last nite's opr session a couple of cars kept coming uncoupled. Seems like part of the knuckle was opening up and not closing causing the cars to come apart. Anyone else ever have this problem? If so, what can be done to remedy it or avoid it from happening again. Thanks.


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## Trains (Jan 2, 2008)

I been using 831's for a long time and never had any problems. 
Make sure the little spring is on the side of the coupler to keep the knuckle shut.


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## chuck n (Jan 2, 2008)

Also check to see if they are at the same height. If they are not, a slight uneveness in the track it will result in uncoupling. Do they come uncoupled at the same place? If they do, check the track!! 

Chuck N


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## Greg Elmassian (Jan 3, 2008)

Check for free operation, you might remove the knuckle spring and check that everything moves freely. Sometimes if they get a lot of moisture, you can rust the metal pivot pin. 

Also check for free movement in the draft gear box. 

The only problems I have had were poor mounting (knuckles ride up over each other), or abrupt vertical grades on body mounts on long cars (and if you are using 831's you are probably truck mount). 

I also had problems on Aristo HW passenger cars when truck mounted, the coupler tang is long and would deflect up and down under load... body mounting fixed that. 

Regards, Greg


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## llynrice (Jan 2, 2008)

That you are using truck-mounted couplers might have some connection to the problem. Larry Green and I both convert all of our rolling stock to body mounted Kadee couplers (I normally use #789 and Larry normally uses #830) and we have found them to be pretty much bomb-proof in normal operation - even on rough track in temporary club layout displays. Wish I could offer more help with yours.


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## Fred (Jan 2, 2008)

Uncoupling came about on level track and couplers matching up perfectly, side springs intact. 
Greg, you mentione a piviot pin, cars were recently subjected to a summer rain.


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## NTCGRR (Jan 2, 2008)

not to often but I have heard of side springs braking and or you might replace it simply because they always give you extras.


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## aceinspp (Jan 2, 2008)

Are the knuckles open or closed when you have the uncoupling problem? If open then may be a weak spring, if closed then you have by passed couplers due to track conditions or poor train handling. Later RJD


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## Bill Swindell (Jan 2, 2008)

When you use truck mounted couplers, there often is a large offset in the mounts. This allows the coupler to flex downward under load and uncouple the cars from the engine. I spoke with Kadee about this problem and they claim that the problem is in the coupler mount and not in the coupler itself.


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## Greg Elmassian (Jan 3, 2008)

They are mostly right, you see I mentioned poor mounting first. 

But, the couplers have a lateral mold line. molds cannot be perfectly straight up and down when in 2 pieces, so the "mold line" inside the coupler knuckle is a bit of a high spot... when pulling long trains, it's advisable to take a small needle file and a few swipes to make the inside flat. Otherwise, the high spots inside can start to offset the couplers under a lot of tension. This is a case where you have like 30-40 cars, which is not your case I suspect. 

I suspect the free movement issue... 

Regards, Greg


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## George Schreyer (Jan 16, 2009)

couplers that line up perfectly in a static test can move under load, especially truck mounted offset couplers like #831's. Due to the offset a buffing force applied to the coupler will make it want to dip downward. If one car's mount is stiffer than the one it is coupled to then one coupler will dip and the other won't. 

Take two offending cars and put them on the track and try to pull them apart while jiggling them some. You'll probably see that one coupler moves downward with respect to the other allowing them to slide over each other. This problem is more severe with the smaller #1 scale couplers. 

There are ways to arrange truck mounts to prevent the couplers from dipping. see the link for some examples on Aristo cars. 

http://www.girr.org/girr/tips/tips2/aristo_car_tips.html#couplers


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## San Juan (Jan 3, 2008)

If they got rusty or just clogged with dirt/debris, the coupler knuckle part may not fully close or open. If they are coming apart on their own free will, then they likely are not closed enough.

I had this happen to my Hartland gondolas and Kadee 831s. They were left out fully exposed for a whole summer and were in a pit too. When the monsoon rains came the cars got filthy. I didn't know it, but the insides of the couplers were also filthy and the knuckle springs rusted badly. When it came time to run them, I coupled to the cars but they didn't fully couple. I had to physically press the knuckles together to get them to fully close. They held after being pressed. I ended up having to clean out the couplers and replace the rusted springs. They sure do give you plenty of extra springs. No problems after that. 


Now when heavy rains are predicted, I typically cover or bring in fully exposed rolling stock.

I personally see no problems with truck mounted couplers. They have worked great for us. And the bonus is you can bring your trains to layouts with very tight radius curves. Your layout may be wide radius and well graded track, but you never know when the opportunity may come to bring your trains somewhere else.


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## Richard Smith (Jan 2, 2008)

One fix I use as standard on the POC is to shorten the tangs a bit. They are much longer than needed unless you are operating on very sharp curves. I cut approx. (by memory)1/4" to 3/8" off the tangs and remount the 831 box. Just this small amount makes a world of difference in up and down motion. I can back a string of 14 or 15 cars through the "S" curve of a pair of LGB 1600 switches arranged as a crossover without problem. 

I chose to use truck mouted couplers for my own reasons which I won't go into here and they have worked perfectly. I do lube them each Spring and use free rolling metal wheels. Additionally my trains are seldom more than 10 cars long. 

I don't want to start a body mount - truck mount war but in most cases I'm convinced that body mounts are best even though I'm not presently using them myself (like I said I have my own reasons). Body mounts are crucial if you run long, heavy trains for optimum performance. They are much less likely to cause derailments when backing long strings as the force is applied to the car body(s) rather than the trucks which have a tendency to swivel from side to side. Additionally they are prototypical and therefore look better. 

I only mention this in case you are running long, heavy trains. Remember too that you can run truck mounted 831's with body mounted 830's although the truck mounts will be the weak link.


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## Greg Elmassian (Jan 3, 2008)

Richard, what type of lube do you use and how do you apply it? 

Thanks, Greg


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## Fred (Jan 2, 2008)

Thanks for all the info, guess i'll take the couplers apart from the offending cars and clean them out. Usually run trains 5 to 12 cars, all with truck mounted couplers & metal wheels. I know from my HO days body mounted are better but I have quite a few sharp curves & turnouts so truck mounted work better for me.


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## Richard Smith (Jan 2, 2008)

Posted By Greg Elmassian on 27 Aug 2009 11:11 AM 
Richard, what type of lube do you use and how do you apply it? 

Thanks, Greg Greg,

I do exactly what everybody says not to do...3 in1 oil. Keeps the pins from freezing up and seems to hold up for the whole season. I got to thinking that sewing machines have all kinds of plastic and metal parts and it works fine on them, why not on couplers? Since they're elevated above the track I've had no trouble with dirt or anything and they've even operated in the rain.

I seldom mention this because I've heard so many negatives from people about not using 3 in 1 that maybe others have had trouble for some reason and I don't want to lead anyone astray. Personally as with paint I've found most indoor products that work well in the smaller scales are only marginally effective for a more robust outdoor environment. Too, I don't bring the equipment inside as it's mostly all, except engines, stored in sheds on the RR.

As to application I just squirt it on the pins on top of the couplers and let in run down through the pin opening. As they say in the drug commercials:
*Safe, fast and effective!*


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## Greg Elmassian (Jan 3, 2008)

Well theories are just that... no substitute for experience. You have been been doing it for a while so there is no arguing it works. 

Thanks for that, if I get any starting to rust or crud up, I will try it. 

Regards, Greg


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