The link to the Bachmann part doesn’t give a good view, to see if the drive shaft coupling is there or not.
I’d look for any tiny cracks in the drive shaft coupling, and do the CA fix. Make sure both surfaces are clean.
Ed’s link also looks like a fix, if the part is cracked.
Mike.
I’d also attempt the adhesive fix, but with one potential difference.
Straight CA can be brittle, and if there is a cracked part it can cause the bond to fail in shear. Some versions of CA contain a fine elastomer powder, to give a nominally more flexible bond. This used to be readily available in LHS-type stores, and I suspect it may still be found online.
The next-best ‘alternative’ would be gap-filling CA, which may be marketed as ‘gel’.
Be very certain that both the shaft and the inside of the coupling are completely degreased and dry before making the joint; I’d suggest seeing if you can make a thin ‘collar’ of grease or vaseline on the region where the shaft just enters the plastic tower, to keep any CA from wicking in or adhering in there – using the thicker CA will help prevent this capillary action from occurring in the first place, but it helps to be sure sometimes.
If you can, degrease the part of the universal that goes on the shaft completely, and relubricate and reassemble the shaft after the glue has completely cured. Remember that it is moisture that causes cyanoacrylate to harden, so in a tight joint it may take some time for the action to complete; don’t trust the 1-minute hardening claims to get a suitable bond. Any bond that is disturbed or weakened before full cure will NOT spontaneously adhere again, unlike contact cement.
If the part is indeed cracked, and if the crack surfaces are clean and degreased, one effect of bonding may be to seal the crack with good integrity and high strength. It will be at a slightly larger effective diameter than nominal, but will resist opening to more than that diameter when loaded or stressed…
Hello All,
Yes, the drive shaft coupling is there. That’s the point of getting the entire truck Gearbox.
That’s exactly what I did. I am now repairing a second unit and am planning on ordering more replacement Truck Gearboxes. This seems to be a common failure.
To the OP, you can try the adhesive approach but from my experience it just won’t work.
I tried CA, two-part epoxy, styrene cement, I even made a sleeve out of brass tubing and press-fitted it over the cracked coupling…all failed.
Each failed attempt meant I had to go back into the guts of the gearbox and attempt another solution.
It was like fitting wheels to a tomato, absolutely useless and an utter waste of time.
I even contacted Bachmann and spoke to a technician in their repair department and asked if the coupling, shaft and worm gear were available as a separate part from the entire Truck Gearbox.
He told me no. The reasoning was that if the coupling had failed due to age the other plastic parts in the Truck Gearbox were likely brittle and prone to failure too.
I completely agree the Northwest Short Line option is just as viable for a long-lasting repair.
Good luck and…
I hope this helps.
Thanks for all of the insight and options. I think I will opt for the CA glue option first and see what happens.
FWIW I purchased this used on Ebay. I contacted the seller and he was kind enough to send me a replacement shaft. Only problem it was the wrong size.
Anyway will try the glue. Thanks again!