Repairing MTH couplers?

I've had a few MTH passenger cars with the same trouble. Since I never switch, or uncouple the cars in a passenger train, I just glue them shut. There's no reason to spend the $$ to replace them if you don't uncouple them.

I've been thinking about a drop of CA in the knuckle for some of those ... wonder why some manufactures couplers stay shut and others don't work for any reason?  Like the couplers on the Atlas engines ... fantastic!  Snap open and shut, stay shut ... great.  And the Third Rail engines .. good.  GGD cars, ... not so good.

I have a brand new GGD car that has the same problem, it's the UP coach that was lettered wrong as well. I debated whether to send it back, but decided to keep it as is. I'm using it for a private excursion train so I'll just glue the coupler closed on it, if I don't swap them out for kadees like I did on my Daylight GGD cars. 

An alternate to gluing them shut would be extremely small rubber bands, like the ones orthodontists use (if they still do use them). 

There's also the small rubber bands used for keeping braided hair twisted together. Those might be easier to find (convenience stores, Rite Aid/CVS/etc)

---PCJ

It seems to me I read where someone was opening those MTH couplers and stretching the spring a bit.

He also mentioned cutting the spring from a ball point pen to length, those are stronger springs...

Sometimes you can take them off and do a little creative filing of the latch to square it up and make them more reliable.

You're right Russell,

I've used a few ball-point pen springs, which are stronger, last longer and work great!!

Ralph

The one downside of stronger springs is you really have to bash them to couple them. 

I don't see how to take it apart to replace the spring .... it's a problem when one comes uncoupled and I don't notice it before the crash ...

In every instance that couplers open unexpectedly, I have found that the pin which extends up through the coupler is too short and or has a rounded end. I use two solutions:

1. Wrap a small rubber around around the coupler shank which will prevent the bar on the bottom from moving;

2. Build up the pin with J B Weld.

You can download the sketch by selecting the icon below, and using "Save Image As."

I super glue every coupler that wont stay shut. Engine or Rolling stock. Works every time.

Question about using rubber bands (I currently use twist ties from loafs of bread), can you still uncouple them with the uncouple track, or is the rubber band stronger than the magnate?  I want to keep the ability to open them by hand or with an uncoupler.

I doubt the magnet will open them, but probably by hand isn't a factor.