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guys my lionel sd70 ace rear motor is having an issue with the drive train. on a liondrive back drivable motor set up the coupling part that attaches to the motor shaft is not attatched to the shaft tightly. this allows the motor to spin freeley and the rear wheels to not move at all when a load is placed on the engine. the part in question on the motor is not cracked or broken. the lionel parts website shows the motor with this peice installed already. my question is can I find a product that will glue this peice on so it will hold and grip onto the motor shaft or do I need to buy a new replacement motor? I have a photo of the motor below and my part that is given me trouble circled. thanks.


Images (1)
  • Screenshot_20200223-160433: cupling that is causing me trouble
Last edited by Lionelzwl2012
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Roger, try to glue it first as others have mentioned. If that fails, I have a dead motor from one of those engines with the nub still attached. We can try and harvest it, and hope it’ll re-install on your’s still pressed on the motor, and hasn’t spun....again, as Pete mentioned, you’d have to buy the whole motor from me if the glue trick fails...your more than welcome to it.......Pat

Last edited by harmonyards

thanks pat I will let everyone here know if the jb weld works. that is what I was thinking of trying. the amount of tork on this part is why a good strong adhesive is needed. maybee some brand of loctight is needed vrs. the jb weld. I  had not thought about that stuff in a long time.  anyone ever try that on a motor shaft before to attach these parts?

pat will be in touch if I need your part. thanks again. 

There was a thread on this posted in the recent past. I believe the solution was a quality adhesive such as the loctite. (Possibly even suggested by Mike Reagan)

I tried a search but couldn't find it. You could try changing the thread title to " liondrive coupling slipping " or something to that effect to see if those that experienced this same issue chime in with the exact solution.

If you use any Loctite I would recommend no. 609 retaining compound.  If you put a flywheel on with that, it's not coming off.  Ever!  The ball is nylon though, so I'm not sure. 

If you go to, Stock Drive, SDP/SI, or even NWSL, you might be able to find a metal horned ball with the same dimensions and inside diameter that will press onto the shaft.  Affix it with Loctite 609, and it's a permanent solution for you and LionDrive owners everywhere!

The ball is diecast. Nylon would never adhere to the motor shaft. One of the problems of the Liondrive system is both the ball and the coupling it drives are diecast. Both are subject to wear if not constantly lubricated. Few do.

Its a poor design given the ball is not easily replaced. I will not buy any Liondrive engines not only for this reason but they also ride higher than the previous worm-worm gear drives.



Last edited by Norton

Didn’t KLine in its last run use a similar coupler? ....the two I have here are definitely plastic, not was already split in one spot, so I shaved it with a razor blade to see what the material’s plastic for sure.. very hard plastic...but definitely not metal.......these might not be specific “liondrive” couplings, but actually old Kline??....or perhaps early carry over Lionel??.........Pat

john good to know it worked for you. I saw this on youtube on loctights youtube channel and thought this may just work. btw everyone what causes these to work loose from the motor shaft anyway? maybe pulling to many cars? or is it just a bad design by lionel? the engine I have here has sat most of its life on the shelf,not run that often and I baby my engines. I dont abuse them.I do not run them 0 to 60 mph so to speek and start and stop abruptly. I run slow and prototipical  and I keep them properly maintained. I just decided to pull this of my shelf to run it and noticed a problem. then after carefull examination found the falty coupling drive to be the culprit. maybe the elf on the shelf is mad at me.😁

gunrunnerjohn posted:

Bad design IMO.  If they really wanted this to be secure, it should have been a fluted shaft, or at least a small setscrew and a flat on the shaft.  Pressing that little nub on a slick shaft is asking for it to spin the first time it gets a hard shot.  Obviously, heavy loads or sudden jolts would accelerate the process.

The motors are already available with a flat on the shaft and all it would have taken is someone at the wheel to wake from their snooze.          j

Just playing the devils advocate here but there are thousands of Liondrive engine out there and having the drive come loose from the shaft is pretty rare. More common are drive nubs wearing off requiring replacement of the whole motor. I had to replace the motors in a Legacy Baldwin Shark engine that was only a year and half old. It was run often by a local club but no more than dozens of other engines that had ten times as many miles.

This was all about cutting costs replacing steel and bronze machined gears with two pieces of diecast metal.


I've probably handled 60-70 Liondrive repairs, three (maybe four) had the same issue, the nub was loose on the motor.  First one I put in a new motor, then I ran across one with no stock at Lionel, then I decided to try the Loctite.  Let's say three of 70, that's still about 4% of the repairs.  I realize this is only a sample of one, but that's a pattern to me.

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