# Rebuilding & Replacing.



## MrStucky (Nov 28, 2015)

Hi Everyone.
These are photos of my used sd40-2 diesel I purchased over the summer. I took the shell off & noticed a loose wire. I fixed this but ended up cracking the shell. Is the shell worth fixing with Gorilla glue/JB Weld, or is it best to get a new one? I plan on cleaning the whole thing, as the “crud” at the end of the drive shaft doesn’t look normal to me. The motor runs but I think the wheels are out of alignment,& I don’t have an nmra standards gauge. I plan on getting a gauge in the future. My psychologist has told me I should buy everything new, yet the fun is lost in fixing things and seeing how things work.
Thanks


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## traction fan (Oct 5, 2014)

*Unclear photos*



MrStucky said:


> Hi Everyone.
> These are photos of my used sd40-2 diesel I purchased over the summer. I took the shell off & noticed a loose wire. I fixed this but ended up cracking the shell. Is the shell worth fixing with Gorilla glue/JB Weld, or is it best to get a new one? I plan on cleaning the whole thing, as the “crud” at the end of the drive shaft doesn’t look normal to me. The motor runs but I think the wheels are out of alignment,& I don’t have an nmra standards gauge. I plan on getting a gauge in the future. My psychologist has told me I should buy everything new, yet the fun is lost in fixing things and seeing how things work.
> Thanks



MrStucky;

I can't really tell what all is broken on the shell from your photos. After a second look, I see what I should have the first time. The cab is broken off the rest of the locomotive. It looks like it could be glued. You can strengthen the new joint by gluing thin styrene "splice plates" across the inside of each side, and the roof. If the splice plates run the full length of the cracks, the new joint will be quite strong. Engine shells are made of plastic, so you should be able to glue it with ordinary liquid cement for styrene.
I also can't tell much about the condition of the mechanism from the photos. It looks like only one truck is powered by the motor? Looking again, I still can't tell for certain, but it looks like the motor has shafts coming out of both ends. I think I can see a tiny bit of shaft at the very bottom of the photo of the motor. Hopefully that means that both trucks are driven by gear boxes. You're right, the crud buildup on the gearbox is not normal. It should be disassembled, cleaned of all old grease and crud, and lubed with a small dab of new plastic-compatible grease. DO get an NMRA gage as soon as possible! It is an absolutely essential tool for any model railroad. They;re not expensive, and you can order one from www.modeltrainstuff.com Be sure to specify the scale you want. The NMRA gages come in all popular scales.

good luck, have fun

Traction Fan :smilie_daumenpos:


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## holava (Aug 8, 2015)

I side with your psychologist, lol. That was a good one. When I went to Hollywood a screenwriter, twenty plus years ago, a shrink charged $ 150 an hour, so I suppose getting new stuff isn't an option. Yet repairing is definitely fun. Right now I'm in the middle of repairing 8 engines that came slightly damaged/loose in the mail.


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## D&J Railroad (Oct 4, 2013)

Looks like a pretty old loco with the square drive shafts.
I don't think the shell would come apart in a clean break like that unless someone else had tried to kit bash it somehow.


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## Old_Hobo (Feb 20, 2014)

That shell is pretty rough looking.....I'd save my energy for something nicer, but that's just me.....


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## MrStucky (Nov 28, 2015)

Hi Everyone.
My Athearn diesel is powered at each truck by gears. The shell/body cracked right behind the windows when I was adjusting it to the frame, then I picked it up & caused the larger break. I’m glad I didn’t start messing with the mechanical stuff, but I figured it was a buildup of crud & not something I should’ve left as is. I can probably get a new body at Trains & Such the next time I’m in Calgary.


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## wvgca (Jan 21, 2013)

in the meantime i would repair / glue the shell, least amount of money invested, lol 

and practice on the rest ..


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## Old_Hobo (Feb 20, 2014)

MrStucky said:


> Hi Everyone.
> My Athearn diesel is powered at each truck by gears. The shell/body cracked right behind the windows when I was adjusting it to the frame, then I picked it up & caused the larger break. I’m glad I didn’t start messing with the mechanical stuff, but I figured it was a buildup of crud & not something I should’ve left as is. I can probably get a new body at Trains & Such the next time I’m in Calgary.


By the look of it, that body has already been hacked to add the wide cab, as the old Athearns did not have a wide cab on them......that's probably why the body broke in a straight line where the cab joins the body.....

I am going to Trains & Such tomorrow, and I'll see what kind of loose bodies they have, but I won't find one with the wide cab, as they didn't do them on older models....


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## MrStucky (Nov 28, 2015)

Hi hobo.
I'm guessing by your response that I'm out of luck finding a new shell. Its close to Halloween though so I could run the loco & run it like its possessed. I bet I could make a new shell out of clear plastic if I had a 3D printer, then add glow in the dark leds or something similar to make it spooky.


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## Murv2 (Nov 5, 2017)

If the only problem is the break where the cab meets the body, glue some plastic sheet on the inside of the body so it sticks out into the cab area, then put glue on the cab and slide them together. Tester's plastic glue should hold the joint nicely. Just butting the two together won't make a strong joint. Rescuing old hardware is always worth it, for practice if no other reason.


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## MrStucky (Nov 28, 2015)

Hi Everyone.
I was working on my sd40-2 yesterday and had good success. I first used a toothbrush to brush away built up crud, then disconnected the wires. I planned on using isopropyl alcohol to clean the wheels and trucks except I didn’t have much. I sprayed some contact cleaner on the wheels and that worked well, allowing the wheels to detach from the chassis. The problem I have now is the motor, in regards to replacing the wiring. Can I just “pull” the motor out, or are there screws to remove that I haven’t found yet.
Thanks


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## flyboy2610 (Jan 20, 2010)

Someone else has worked on that diesel before you got it. That Mashima motor is not original. It has most likely been glued to the frame. Look under the fuel tank. See if there are any screws in the holes. If so remove them and see if the motor comes out. If there are rubber looking plugs in the holes, use a punch and push them out. I'm betting though that the motor has been glued in, probably with something such as Shoe Goo. Grab the motor on each side and rock it side to side to see if it loosens up.


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## MrStucky (Nov 28, 2015)

hi Flyboy.
There are rubber looking plugs at the bottom & I messed around with those for a bit, but I didn't want to make things any worse than they already need to be. The other thing I noticed yesterday while tightening a small screw on the joints between the worm gear & the motor, that one of the differential joints is cracked. I don't know if this was my fault though or someone else's. I'll post a picture of the problem if you'd like.
Thanks for the tips.


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## flyboy2610 (Jan 20, 2010)

Those plugs are the bottom of the original Athearn motor mounts. It's possible someone figured out a way to mount the motor using the original mounts. Find a blunt object and push them out. They can be pretty stubborn sometimes.


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## pokey_toaster (Nov 4, 2019)

Often the aftermarket motors are stuck in with silicone caulk. If the original Athearn mounts are still there, they were probably just used to center the motor. Mashima is a very good motor.

The model looks to be a kitbash of an SD40-2W. A similar model is now available from Intermountain.
Paul


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## MrStucky (Nov 28, 2015)

Hi Everyone.
I managed to get the motor off the frame and I’ve been scraping away at the black rubbery adhesive, put in place by the previous owner. The wire on top was originally stuck at the bottom, I’m guessing as a ground wire or whatever purpose it is meant for. I included a picture of the bodies internal wiring, and the crack on the driveshaft assembly. I’m not to sure what adhesive to use when I reinstall the motor, but I have No More Nails, CA glue and I believe I have 5 minute & 30 minute epoxy.
Thanks


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## flyboy2610 (Jan 20, 2010)

Actually, Shoe Goo or Pliobond would work well for installing the motor. You want something with just a little bit of give to it.


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## MichaelE (Mar 7, 2018)

I would remove that u-joint and try the AC glue to close the gap. After that sets up securely I would put a light coat of JB Weld all the way around the u-joint for security and prevent further cracking.

A light, even coat. And let that dry thoroughly before re-installation.


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## pokey_toaster (Nov 4, 2019)

ACC/ super glue won't glue Delrin. The motor probably has a 2mm shaft and both Northwest Shortline and Hobbytown of Boston have 2mm connectors. Unfortunately, they are both in transition so their websites are not necessarily current but they will probably answer the phone if you can't find their parts from your favorite retailer.

The black goo was commonly included with can motor repower kits and works pretty well. The usual replacement is silicone caulk, put a small bead where the motor makes contact with the frame and tape it in place for a day while the silicone cures. Also make sure it doesn't touch the inside of the shell. Like Flyboy said, you definately want something with some give to absorb and quiet any vibration from the motor. I find it easier to connect the motor wires before installing the motor.

Paul


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## MichaelE (Mar 7, 2018)

No, it will not. If that is what it is made of.

I would then clamp it lightly closed with a hemostat and then use the JB Weld to form a sheath completely around the outside while holding it closed.


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## traction fan (Oct 5, 2014)

*Replacing or repairing the universal joint*

Mr. Stucky;

If you can find a new replacement fitting, that would be the better option. It's tough to repair a cracked drive fitting and have it stay together under the stress of doing it's job.
If your cracked U-joint is made of Delrin then it won't glue unless you can find, and afford, a specialized adhesive made for Delrin.
If it's made of some other plastic, then CA/super glue, or even styrene cement might work. However because it's slippery, and strong, Delrin is often used for this kind of fitting. You can try the CA and see if it works. If the dried CA can easily be flaked off, leaving the U-joint bare, then it's made of non-stick Delrin.

Delrin can be "welded" by heating the edges of the desired joint with a soldering iron. I do this with the tops of Micro-Trains coupler boxes, which are made of Delrin. I've had several couplers come apart, including the more expensive, factory-assembled ones. :rippedhand: In those cases the factory welds were not done as well as they should have been.

Doing this on your U-joint would be a challenge. You would need to melt the Delrin along the length of the crack and move the soldering iron side to side across the crack to overlap a little of the Delrin plastic over the crack. Even if you managed to do that, there's no guarantee that the weld would hold together on a moving drive component. The coupler boxes aren't under the same stress.

I've not used the JB weld, that MichaelE recommends, but I like his idea of putting some sort of containing sleeve around the outside of the U-joint. I'd be inclined to use brass tubing, if I could find a size that fit, or else heat shrink tubing. However Michael seems to be a quite knowledgeable modeler, so the JB weld may work equally well.

Good luck

Traction Fan :smilie_daumenpos:


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## traction fan (Oct 5, 2014)

*Rebuilding or replacing the cracked universal joint*

Sorry, duplicate post.

Traction Fan :smilie_auslachen:


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## MrStucky (Nov 28, 2015)

Hi Everyone.
I’m in the process of soldering the wires into place, but I did get results using my power supply, and a couple wires connected to the motor and a powered truck. I remember before I took this sd40-2 apart, the driveshafts were at more of a downward angle instead of almost horizontal in the photo, as I was hearing a buzzing & the wheels weren’t turning at the trucks. The other photo from the end shows, that the motor isn’t properly level. I used Shoo Goo to reattach the motor, & I have a feeling that I’ll need to make some adjustments in order for the gear mechanisms to work properly.
Thanks


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