Locomotive drive line slippage plus

[seaisleRR]

I did some toubleshooting today and found that I have a problem with a GP 38-2 (Norfolk Southern) loco. Good looking little loco!
At first I thought it was the wheels slipping as it goes up a 3% plus grade. All my other locos can pull at least 4-6 plus cars with only the
usual slowing because of the combo of the grade & cars. I have pretty good transitions and clean track on this layout using the
Woodland Scenics Subterrain system. I'm at the stage of the final smoothing/etc. of the foam risers transitions before laying plaster cloth,
then the track bed and final laying of the track. My first 3D layout... ...other than the single raised bridge w/ piers on a flat layout
many moons ago.

Back to the locomotive problem.
I opened her up and proceeded to clean the wheels and noticed that the back wheels stopped as I put only minor to mid pressure
on them down om my cleaning towel. Turns out that the slippage is occurring at the plastic "U" joint that connects to the metal pin on
the worm gear. Only on the back truck. The front is doing fine. It's just a DC loco, but it's still one of my favorites.

Anyone have a good fix for the problem? As I was writing the first part, a possible fix occurred to me. I was thinking of putting a TINY
dab of liquid electrical tape into the "U" joint hole and let it cure a good bit before I slip it back on the worm gear pin.
Might this work or is there a better fix?

I was looking in the latest Micro-mark catalog. Found a kit with synthetic oil and grease, "Nye" brand, and they say it works much better
than regular petroleum based lubes. Has anyone used this stuff and do you recommend it?
Also... Would any of you recommend using "Bullfrog Snot" on my wheels if I might need a little more traction? Not on all wheels of course,
as it is non-conductive.

[Jim Banner]

seaisleRR,

I am assuming the "metal pin on the worm gear" is the axle shaft through the worm gear with the plastic U-joint cup press fitted on the end.  These cups sometimes split, usually in line with one of the slots.  If yours has split, it will slide off quite easily.  If this is the case, putting liquid tape in it might work but it might equally well just force the split to open wider and start slipping again.  An alternative that I have had good luck with is putting a collar on the outside of the cup, around the part that is not slotted.  You can make up a collar by winding a single layer of fine wire around the cup, keeping the wire tight all the way.  If you start wrapping near the middle of the piece, you can hold the wire in place by passing it through the slots, giving it a couple of turns over the slots, then passing it through the slots again.  When you get to the worm gear end of the cup, you can hold the last few turns in place with a small spring clamp or a clothes peg.

Next, saturate the collar with ACC ("Crazy Glue") to hold everything in place.  The ACC between the coils of wire will set quite quickly if the wires are tightly side by side but the ACC trapped in the triangular space between wires and the cup may take a couple of hours to set.

When the ACC is fully set, trim off the wire you put through the slot and any wire left over at the other end.  The cup should now be much tighter on the worm axle shaft than it was before, probably tight enough that all you have to do is push it back in place.  If you feel it is still a bit loose, put a small drop of ACC inside the axle hole in the cup and then press it in place.  Do not put ACC on the shaft as pressing the cup in place would very likely push the excess ACC into the bushing next to the worm.  Let the ACC set for several hours, or better, overnight before putting the end of the drive shaft into the U-joint.  You really do not want to get ACC on it.

Sorry that I cannot offer any advice on Bullfrog Snot other than to offer the poor Bullfrog a Kleenex and condolences.  (Sorry, bad joke.)  Perhaps one of the others who regularly post here have used it and let us know how they like it.

Jim 

[seaisleRR]

Thanks for the tip on the U-joint cup split possibility Jim. I looked at it when I took it off, but didn't notice what I now can see
upon closer inspection. I almost need a microscope to see it. It's not too long (maybe 1/16" plus a hair or 2) and it's 90 degrees
off of the slots for the plastic 'drive shaft'  pins from the motor. So, I hope that the cup won't totally break. ...Knowing full well
that it may in the future. I'll clean it up really good to get as much of the grease off as possible and try your fix.

[seaisleRR]

Forgot to ask a question. To any and all who may know. Does anybody sell replacement cups? I see in the parts department that
they sell complete truck assemblies with what looks like the U-joint cup in question. Too bad they don't just sell cup. My loco is
almost brand new and maybe has 40 minutes total run time on it. And not rough handling either. Leads me to think it may have come
that way out of the box. It was brand new when I bought it.

[bobwrgt]

Call the service department at Bachmann and tell them you want to talk to a service tech. They will probably send you some cups at no charge. Most of the time they have parts that are not listed.
Jim has a very good solution. In the past all i have done is add a drop of superglue inside the cup and let it dry. Has been working for a few years now.

Bob

[Jim Banner]

Sorry, seaisleRR, I didn't realize your locomotive was new.  This being the case, I agree with Bob - phone Bachmann service and see what they can do for you.

Another suggestion, if I may.  Perhaps you should start a new thread asking for people's experience with the Bullfrog Snot.

Jim

[seaisleRR]

I failed to mention that it was almost new. Been in the box - unopened for over half a year waiting for me to get to the point of running it's
break-in on my new layout. So, until you told me to look at the cup closer Jim; I didn't think it mattered if it was new. I'll most surely give
the Bachmann service a call and hope they'll send me a half dozen. Heck, I'd be willing to pay them a little shipping for the favor.