AX15 Input Shaft Repair

XCRN

XCRN

TJ Enthusiast
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Springfield OH
So pilot bearing took out the input shaft on my AX15 from my install mess up. Looks like where the pilot bearing goes it wore down that part of the shaft. Before I start the process of replacing the input shaft on my AX15, is there a way to repair the tip without stripping down the trans? I want to explore options before going all the way with this.

IMG_8373.jpeg
 
Weld it and "machine" it down spinning the transmission.

Wonder if you could press a thin, correct sized piece over that.

Wonder if they make oversized pilot bearings.

-Mac
 
macleanflood said:
Weld it and "machine" it down spinning the transmission.

Wonder if you could press a thin, correct sized piece over that.

Wonder if they make oversized pilot bearings.

-Mac
Click to expand...

That what I was wondering. Something like can you spin the tail shaft with a machine and use a cutter like a lathe to machine the tip down and put a sleeve on.
 
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XCRN said:
That what I was wondering. Something like can you spin the tail shaft with a machine and use a cutter like a lathe to machine the tip down and put a sleeve on.
Click to expand...

Problem of course with that is there is a lot of end play in that shaft...why there is a pilot bearing in the first place. You'd need a roller fixture to secure and center the shaft.

Basically take apart a lathe and I'd take off the bell housing and figure out how to bolt something up you could fix rollers and a carbide bit too.

But honestly an AX-15 comes apart so easily...be worth rigging up if I owned a shop and this was a frequent repair...but then I doubt I would do this for a customer...

Mountain to Mohammed question...do you bring the shaft to the lathe or the lathe to the shaft.

-Mac
 
macleanflood said:
Problem of course with that is there is a lot of end play in that shaft...why there is a pilot bearing in the first place. You'd need a roller fixture to secure and center the shaft.

Basically take apart a lathe and I'd take off the bell housing and figure out how to bolt something up you could fix rollers and a carbide bit too.

But honestly an AX-15 comes apart so easily...be worth rigging up if I owned a shop and this was a frequent repair...but then I doubt I would do this for a customer...

Mountain to Mohammed question...do you bring the shaft to the lathe or the lathe to the shaft.

-Mac
Click to expand...

How far do I have to go to get the input shaft out? Most rebuild videos they go to the very end to take the shaft out but I think its because they are rebuilding it all the way so it does not matter to them. Looking at the cluster seperated from the case I could pop it off before removing all the shift mechanism. But its hard to tell. Just not super thrilled to take apart a new transmission but is what it is.

I did however see this, might be an option to explore. Only problem is this trans is backing an LS so I am using a different larger bushing to go into the crank so ill need to custom machine something else to reduce it to the new larger pilot bearing size.

https://www.fitzall.com/KPBD57HD.php
 
Does anyone know what an acceptable amount of wear is? Before I was able to clean the shaft I took some calipers to it (I know not the most precise method but its what I had) and got any where from 0.748 to 0.752. I am considering the idea of going with a bronze bushing since that is how Novak does their conversions with AX15s.
 
macleanflood said:
Call Novak and ask? I'd certainly be curious what they say.

-Mac
Click to expand...

They definitly think the bushing can be used. I cleaned the tip a bit and measurements came in closer to 0.746 to 0.748 so I think that would be acceptable range. There was a slight grove around it my finger nail would catch, but when going to a bushing instead of a bearing as long as I remove the high spot it should be alright I would think. I just don’t trust a bearing on a now imperfect surface.

I was doing lots of searches of bushing vs bearing and sounds like bushing should be more reliable anyways. I had a bushing for the first 30k miles in my swap until I went a whole new setup that included a pilot bearing so might as well go back to that.
 
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Yeah bushing vs bearing is a religious argument and everyone is right and everyone is wrong.

Bearings typically come in set sizes... bushings can be turned in a lathe to whatever sizes and tolerances you desire...and so...right or wrong... it's a good choice.

I'm curious what it looks like the next time you take it out...keep me, us updated!

-Mac
 
macleanflood said:
Yeah bushing vs bearing is a religious argument and everyone is right and everyone is wrong.

Bearings typically come in set sizes... bushings can be turned in a lathe to whatever sizes and tolerances you desire...and so...right or wrong... it's a good choice.

I'm curious what it looks like the next time you take it out...keep me, us updated!

-Mac
Click to expand...

This is the original bushing that I put 30k miles on before swapping setups. Not the best pics, just zoomed in screen shots of what I had on my phone.

IMG_8389.png


IMG_8388.png
 
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