JB Weld or Better?

BobnUt

Member
I have an accessory drive shaft coming out of a Allison tranny. It is a female spline that has been wallowed out over 50 yrs. 5 years ago I rebuilt the vane pump with new 1" male splined shaft, worked fine, but now it has failed again.
So, since I can't pull the trans, I have to 'epoxy' it together and hope for the best. Question then, what is the BEST to use in this situation?
Thanks for any expertise!
 
Loctite makes a retaining compound that is just for splines and filling gabs. It will work much better than JB weld. The Loctite compound will work better.
 
I"m guessing you mean the female splines in the transmission are what is messed up. If that is the case your pretty much out of luck trying to repair it with anything other than a new piece in the transmission, with good, metal splines.

Think about it like this. The metal is a lot harder, and stronger than pretty much any type of epoxy you could use, and it"s still wearing out, so it stands to reason that the epoxy isn"t going to last any amount of time at all. I am basing what I say here on seeing where others have tried something like this, usually as the one that has to pull everything apart to fix it right, and the results they have.

That said, there are places that can take the old part out of the transmission, build it up, anc cut new splines. Better yet they can probably also take the old part, bore it out to a straight bore, and put a keyway in it. Given that the pump is showing it"s age also, this would give you the capability to get a more standardized, straight shaft pump, with a key, and change it at the same time.

Not knowing more about the whole setup, or being able to actually see things for myself, I"ve got to say I think second option as being the best one, and the one that"s going to be the cheapest and last the longest for you. In the end short of welding the pump shaft to the piece driving it, there really isn"t much else you can do that"s going to last beyond a very short amount of time before your right back in the same boat again, and it will probably happen at the worst possible time.
 
How reliable do you need it to be? If the truck is a backup unit, another cheap fix might work for awhile before it fails again. If this is your main truck it could also fail at the worst possible time. On a 50 year old truck you might be able to replace the whole truck for less cost than fixing the transmission.
 
i think i'd weld in a sleeve inside the wallowed out area.. that sleeve would be something that had an internal dimension i culd use for the shaft.

IE. weld in a deep well impact socket after cutting to length and turning the outside so that it could be driven in. weld the face up then adapt the shaft to hex..

that or some kind of 'slot' drive.
 
BobnUT:

I have to agree with NCWayne. Having worked as a Mine Maintenance mechanic I've come across situations similar to yours. JB Weld (epoxy) is a great patching material, but it does NOT hold up under torque or vibration situations.

Doc :>)
 
Thanks for your suggestions guys.
This is a loader/backhoe and getting the trans out is not worth the time, money, or busted knuckles.
It is a oil charging pump for hydraulics, turns at engine speed, so I don't believe it has tremendous torque like a driveshaft.
I did some research and found a product called Belzona. Here is a link to what they accomplished...
It is pricey, but if I never do it again, worth it.
spline repair
 
I used Belzona to repair a shaft in a nuke 25 years ago. It ain't a cheap fix but it's probably stronger than the original steel!
The shaft was worn from the bearing having puked and the plant guys didn't/couldn't repair it until an outage.

The instructions said to build up the damaged area and turn it in a lathe to get it back to the original diameter. It said to turn it before it was fully set and hardened.....I did it and it worked great but that's the only stuff I've ever seen that *rounded* the lead edge of a carbide lathe tool!

There's different grades but a 9" side grinder wouldn't the stuff we used!
 

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