Dear Märklin friends,
I found a low-sided 8610 wagon on eBay, but unfortunately, one of the two couplers doesn't return to the correct position on curves, due, I suspect, to a defective spring. I'm sure that years ago, for a similar problem, I found both instructions and videos on YouTube explaining how to replace the defective coupler. Also, can you please tell me the exact original spare part number for replacing the couplers? Is the number E166264 (Kupplung lang) the correct one?
Thank you in advance for any help you can provide!
Sincerely!
Prof. Stefano Rocca

Thank you for your advice! yes, mine is this
1000034658.jpg (3,372kb) downloaded 8 time(s).
I'll try to replace it on my own!
Beste regards
Stefano Rocca

Yes, E166264 contains 10 couplings and 10 springs. That's 1 pair to do the job and another 9 to spring off the table, never to be seen again.

Cheers


Chris

I suppose my first question would be whether you really need to disassemble the truck at all? Z scale couplings aren't fool-proof and I certainly have difficulty sometimes coupling trains together, even on the straight. The couplings don't always return to the central position even when everything is as it should be.

If you are sure there is a problem with this truck, could it be corrected without disassembly? It seems unlikely that the spring would get damaged, but perhaps some foreign matter has got into the pocket? I would try flushing it out with an aerosol solvent such as WD-40 Contact cleaner (NOT regular WD-40). Alternatively, you could apply some Iso-Propyl Alcohol via a dropper or syringe. Flood the coupling pocket, gently work the coupler back and forth then drain as much of the solvent as you can. Repeat this a few times - I think there's a good chance it will clear whatever is causing the problem. Do be cautious about the solvent you use as some can damage plastic. The two I mention should be OK.

If you do feel it's necessary to dismatle the wagon, make sure your work area is as clean and clutter free as possible. I'd suggest you use an old cardboard box as a work cabinet to contain any items that do make a bid for escape. I have also heard people suggest you put everything in a clear polythene bag and do the work it there. Don't even start without some magnifying goggles of some sort and make sure you have plenty of light.

I have attempted a coupling replacement like this once before and it doesn't seem possible to do an "as new" repair as it's not really possible to unsecure the pin that goes through the coupling pocket without cutting away some of the melted plastic, which doesn't leave enough to melt over and hold everything together once te repair is complete. To further complicate things, the plastic used doesn't seem to respond to usual plastic weld solvents so it's not possible to do a precision patch using the solvent to bond on an additional piece of plastic.

If I was attempting this repair, I think my approach would be :

• Carefully cut away the melted plastic around the pin of the coupling pocket for which you want to replace the coupling.
  Put the wagon in a clear polythene bag and prise apart the body shell from the chassis moulding at that end. I think there should be enough play to do that without disassembling the other end.
  Once the pin is clear you will be able to withdraw the coupling hook and its spring with it
  To reassemble you need to insert the spring into the pocket followed by the coupling hook itself There is a "pip" in the hook which locates into the centre of the spring and I think there's something similar in the pocket as well.
  Once the hook is in position you can close the body shell and chassis back together - the pin goes through the hole in the coupling hook so it is quite fiddly.
  If you're lucky, there will be just enough of the pin left to melt with a fine soldering iron bit to keep everything together. Alternatively, you could use a dab of glue between body shell and chassis to hold everything together. I think that's what I ended up doing.
  

As far as I know, this isn't a common problem and I've not seen any instructions online on how to do it, so I hope these thoughts are helpful.

As I said earlier, though, I'd initially focuss on clearing the problem without taking anything apart.

Good luck


Chris