Driveshaft spline wear

35ragtop

35ragtop

Senior Member
Hi all,
I am wondering if anyone has tried this idea? (1948 Mercury)
The splines on the diff end of my solid driveshaft are worn so that the spline coupling is a bit sloppy. Getting another driveshaft in premium condition is almost impossible, so Im wondering if welding the coupling onto the driveshaft would work. The earlier V8,s had the coupling welded onto the hollow shaft.
Are there any metallurgy issues with doing this?
I would like to know what others have done, as getting the shaft built up and re-splined is a big deal cost wise.
Dave
 
I think your idea is sound....you're lucky, normally it's the pinion end of the coupler and pinion splines that wear; a harder fix. Keep it all aligned when you weld it; set it up in a lathe .
 
No doubt welding will work. You might want to consider plug welding the drive shaft by first drilling holes in the coupler as well as a circular fillet weld around the end of the coupler.

But, first read the rest of this post, including the red ink.

I can't help but think that there must be some way of building up the worn splines so that you could mate the coupler onto the drive shaft so its nice and tight and still pin it to the rear end spline as when stock. That way the drive shaft is still removable if you remove the coupler pin.

How are worn splines repaired in other situations?
Here's a whole lot of helpful info. on how to repair worn splines.
https://www.google.com/search?q=how...ome..69i57.10375j0j4&sourceid=chrome&ie=UTF-8

EUREKA! Just found this.

I think this product from BELZONA will solve the problem. Amazing stuff for repairing worn out splines. Watch the video.
https://www.youtube.com/watch?v=nN8R0TrQOiA
 
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Yes; I used the Loctite product on pinion spline for a '37 diff. Just note ther is a primer and an activator. got the products fron Fastenal , cause they have to be shipped ground... Amazon could not ship them. Newc
 
what wear...???
 

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Rob you could fix that with Araldite! LOL!
I have done some research on those epoxy products. Obviously the more expensive ones, are better , one would hope. locktite Fixmaster Superior Metal is a alternative to the Belzona product. They show examples of using it on heavy farm machinery splines, so it may work. The trouble is, if it doesn’t, there is a lot of work to take it apart again and I’m not getting any younger!
Thanks for your input everyone.
Dave
 
And if it doesn't work it will bugger the pinion bearings as it migrates to the rear end.
I know.I never cleaned out a machined driveshaft and the swarf did them in
Lawrie
 
I tend to agree Lawrie,
after that spring tour that we called in to see you, I pulled the diff out of my 38 because of a noise and found that the ch....se made 6 spline coupling had worn and the filings had migrated into the ring and pinion. Another $1400 for parts ( ring, pinion, bearings, seals etc.) The thought of that strong epoxy granular wearing away and dropping into the diff worries me.
I’m heading off to see if I can get one end of a coupling welded to the solid driveshaft .Afterall the early 30s cars only had one end pinned.
Dave
 
I will just clarify my above statement re the parts I replaced. I did replace the ring and pinion but it was to go from a 3.78 to a 3.54, not because of damage. The bearings were stuffed and quality Timkens were around $600 for the full set.Dave
 
Maybe that's why Ford made the shaft & pinion one piece in those early years of the Mercury. Maybe they shouldn't have stopped doing that.
 
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