On my new Santa Fe, the front coupler is coming unlatched with no electric. I snipped the wire and it will still unlatch for no reason. I was wondering what is wrong and if it is even fixable.
Who's the manufacturer ? Brand name ?
Here's a picture from the 2330 service manual that shows how it works: http://pictures.olsenstoy.com/cd/locos/loc2330c.pdf. Knuckle TC-21 is held shut by plunger TC-113, which is pressed by spring TC-112 against the cam-shaped back of the knuckle. If the locomotive wheels lose contact with the track, it is possible for the return current to flow through the coupler to whatever is coupled to it. If it momentarily flows through the springs, it can overheat them and cause them to lose their temper. The knuckle spring is the usual victim, but the plunger spring is also vulnerable.
You can test the spring by pushing the end of the plunger with a slender probe while the knuckle is closed. The normal force is probably too weak to feel; but you can observe whether the plunger returns reliably to the cam when you release your pressure on it.
If this is the problem, you will need to remove the knuckle to replace the spring. Note that the plunger and the spring are symmetrical; so it doesn't matter which end goes in first. If you've never replaced a knuckle, say so; and I can give you some tips.
Bob Nelson
I have never replaced one, some tips would be great. I assmume I will have to order a spring and rivit?
For the person who asked the brand, it is a Lionel Postwar 2343 Santa Fe.
Did you determine that the plunger spring is weak?
Drive the pin out from the bottom with a slender icepick (or something of similar shape). Prying from the top will probably mar the coupler. The icepick follows the pin through the coupler and keeps everything together. And you can likely reuse the pin, which will be a press fit through the hole because of the slight flare left in the riveted end.
After replacing the plunger spring and reinserting the plunger, put the pin in halfway, put the knuckle spring onto the pin, then put the pin in all the rest of the way. Next, put the knuckle in place, with its hole next to and pressing against the side of the pin, with the knuckle spring in position at the top of the coupler. Gradually withdraw the pin, sliding it along the knuckle and keeping the spring in its place. When the pin just clears the knuckle, slide the knuckle's hole into line with the pin, which is still retaining the knuckle spring. Then push the pin through the knuckle and all the way back in. Flare the pin just enough to keep it in place, no more; and it will be easier to remove the next time.
Yes my spring was broken in two. Now what? Where would I find that small spring?
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