Transmission Tail Shaft Break-out Repair ideas

[zKars]

I have an early 5 speed here (77-79 “B” type 5 speed) that I’m rebuilding that has a busted out tail shaft casting where the output driveshaft seal goes. Was apparently dropped at some point in it’s life, the dust shield is clearly bent and re-shaped by a PO.

I’mm looking for brilliant and inventive ways to fix this (I mean cheap…..)

 

Edited April 10, 2024 by zKars

[zKars]

I ground out the edges of the broken area to freshen them for welding or glueing or something. 

The P0 had put a large blob of RTV or similar over that area, no idea if it leaked there or not. This trans was pulled from a 78 in a junk yard 15+ years ago.  Internally it’s a thing of beauty. Not going to do much with it, but I have to do SOMETHING with this tail shaft.

You can see in the first picture with the seal back in place, that just gooping it up with RTV/Right-Stuff “might work. There is enough of the circumference gone though that the seal might be pushed out-of-round enough to allow a leak. 

Edited April 10, 2024 by zKars

[zKars]

While i do have a TIG welder and a mill, I “could” build up that area then mill that back to a nice circle on the ID. Trouble with TIG welding I find, is that unless you practice alot, (which I don’t) that the chances of making this worse before it gets better are pretty high. 

I was thinking take a piece of 1/8 aluminum plate, bending it in a nice matching curve, trim to fit that missing area, and then solder/braze it in place from the outside. I some of these fancy torch melt low temp aluminum brazing rods that I have used in the past. 

Then once it all setup, mill the ID to right size if its not super close to start with, then add a bit of goo on the new seal OD to fill in any imperfections and call it a day! 

What you-all think?

 

[Yarb]

What’s the possibility of somebody out there having a tail shaft housing they no longer need for whatever reason. You never know….

[Patcon]

4 hours ago, zKars said:

While i do have a TIG welder and a mill, I “could” build up that area then mill that back to a nice circle on the ID. Trouble with TIG welding I find, is that unless you practice alot, (which I don’t) that the chances of making this worse before it gets better are pretty high. 

I was thinking take a piece of 1/8 aluminum plate, bending it in a nice matching curve, trim to fit that missing area, and then solder/braze it in place from the outside. I some of these fancy torch melt low temp aluminum brazing rods that I have used in the past. 

Then once it all setup, mill the ID to right size if its not super close to start with, then add a bit of goo on the new seal OD to fill in any imperfections and call it a day! 

What you-all think?

 

I think that's a decent plan, if it works out. I have never done any aluminum welding. Cody has taken a stab at some Aluminum TIG work and it can be unpredictable.

[grannyknot]

5 hours ago, zKars said:

 

I was thinking take a piece of 1/8 aluminum plate, bending it in a nice matching curve, trim to fit that missing area, and then solder/braze it in place from the outside. I some of these fancy torch melt low temp aluminum brazing rods that I have used in the past. 

Then once it all setup, mill the ID to right size if its not super close to start with, then add a bit of goo on the new seal OD to fill in any imperfections and call it a day! 

What you-all think?

 

I think this is quickest, least expensive remedy, the repair really only has to keep the trans fluid in.

[Namerow]

Counter-thought:  You say that you have a mill.  Cut off the end of the housing at a point just past the deepest part of the gouge.  Now mill out the ID of the remaining housing wall to half the original thickness.  Make the milled-out area as deep as you can.  Find some aluminum pipe with about the right ID and OD.  Machine outside and inside surfaces to get the correct final ID and OD.  Now cut a stepped-down length of OD to match the ID of the undercut that you created in the housing.  Aim for an interference fit, where your new piece would be chilled and the housing heated before assembly.  Maybe add a few drop of the appropriate type of Loctite for extra security.

It's hard to see from your photos whether the stub of good housing that sits below the gouged out section would be deep enough to make this sleeve approach work reliably.  I would think that a drop-in length of 1/2" would be adequate. 

[Zed Head]

You could mill the remnants completely off of the tail shaft and replace it with a tubular piece with an interference fit.  The mani concern would be if it fits inside the dustshield of the propeller shaft.

Namerow had the same thought, almost exactly.  I'm slow...but I drew a picture.  It would be much stronger.

 

[zKars]

 All interesting ideas.

Perhaps if I can find a slightly smaller OD seal, I can just make a thin liner pipe to go inside the current ID (50mm) that brings it down to the size of said smaller OD seal. Kind of an inside out Speedy Sleeve!

The stock seal fits our 35mm driveshaft sleeve and a 50mm tail housing ID. Like a Timken 710324. So maybe a make a 48 mm ID

Start with a 2” OD aluminum pipe with 1/8 wall and turn the outside to 50.05m and the inside to 48 or whatever seal I find. ? Maybe

Anyone know how to search a seal catalogue by OD/ID? 

Edited April 11, 2024 by zKars

[zKars]

 Here is one idea I started with tonight.

Make a fitted backing plate of something my low temp alloy rod or TIG bead won’t stick to, then merrily go weld beads to build up the missing piece.  Brass may not be the right material, sheel steel is likely better, but you get the idea. 

While doing this I dreamed up the liner with smaller seal idea above.

 

[Patcon]

Copper would be my choice for backing

[Zed Head]

Found a seal search web site for the internal repair option.  Might be a skinny seal.   

https://engineering.timken.com/engineering-tool/seal-search/