question about SOA/cut and turn (1 Viewer)

[tfdcruiser]

I was wondering about another possible way to cut and turn for SOA. Let's say you want to go SOA, could you first go ahead and weld your top spring perch parallel (or slightly angled for ideal caster) to the existing bottom perch and now go ahead and mount up your axle. Now the pinion angle will be pointing in the wrong direction but your steering geometry should be preserved since all you are doing is placing the spring on top of the axle. Now could you just take a heavy pipe cutter and cut the axle tubes somewhere in the middle (or wherever is convenient) and now rotate the differential upwards as needed and reweld the axle tubes. You could reinforce the rewelded area by plating with a piece of pipe cut lengthwise and welded over the joint.

If this has already been done or if this is an unoriginal concept please let me know but it seems like it would be easier and faster than first setting the pinion and then cut and turning at the knuckles. In my mind it would be easier to accurately set the pinion angle by cutting and turning at the axle tubes, you could scribe a mark along the axis of the tube and cut perpendicular to the mark. To ensure the tubes remained straight you could set them in the vee of a heavy piece of four or three inch angle iron and clamp them down before you reweld.
Let me know if this makes sense or if you know of why this wouldn't work but to me it seems that it would be faster and easier than the traditional way.

 

[FJ40LVR]

If I had to guess why this is not as common practice, it would be because of the thickness of the tube at that location, which is thinner than at the reccomended cutting location which is where the factory weld is at the end of the tube, @ the knuckle, where the housing has more steel to resist warping under the heat of the rewelded seam.
Other than that, I can't see any reason? be sure to check out all the check out all the technical links under the suspension section here:
http://www.ih8mud.com/cruisertech.php

 

[tfdcruiser]

Are you saying that the axle tube thickness is tapered to be thicker at the ends or that the knuckle provides mor suport material to weld to? If the latter is true then I think you could regain or surpass the strength by plating and/or gussting/trussing the axle in that area. Do you or others concur that it seems simpler this way or is there a fatal flaw in this method that I m missing. thanks, don.

 

[inkpot]

Are you saying that the axle tube thickness is tapered to be thicker at the ends or that the knuckle provides mor suport material to weld to? If the latter is true then I think you could regain or surpass the strength by plating and/or gussting/trussing the axle in that area. Do you or others concur that it seems simpler this way or is there a fatal flaw in this method that I m missing. thanks, don.

Howdy! Interesting idea, but, the conventional method of cut-n-turn is much better. The knuckles literally slide out and back in once the welds are removed. No risk of structural compromise, as it does not remove or cut into any parts. It also does not need any extra gussets to support it when reassembled. No chance of loosing the critical line up of the axle shafts in exactly the same plane. Cutting and re-welding the center section might warp the housing, and you would have to remove the axles to protect them and clean it all up when your done. Much of the housing is egg shaped, so you could not do just a basic butt weld to put it back together. The passenger side of the housing does not offer much room between the pumpkin and the spring perch to do any of this, especially as it would require lots of gusseting. This is all based on a LandCruiser axle.

Now, if you want to do this on a domestic axle, like a Dana 44/60/70, then it's a piece of cake. They are built from two sections of straight tube pressed into a center housing. You can pull the tubes and index them however you would like them.

Didn't mean to rain on your parade, but I spent a lot of time looking for an "easier way" for me to do it on my Piggy, and I decided to go "conventional". John

 

[FJ40LVR]

Are you saying that the axle tube thickness is tapered to be thicker at the ends or that the knuckle provides mor suport material to weld to?

The latter - support. As John B. commented, the knuckle factory weld is cut through, the sleeved knuckle (inside the axle tube) is rotated and re welded, in the same place - without worrying about keeping the strength integrity of the housing during reweld, or keeping it completely straight (as much) and without adding additional exterior stiffeners to the axle tube itself.

I am about to undertake this project as well, in order to correct some front driveline issues I currently have.

I have personally never seen a LC housing cut in the manner in which you are explaining, but that does not mean that it can't be done, or that it shouldn't be tried! I might even have an extra housing to practice on!

 

[RHINO]

another thing to remeber is that the C&T is a two fold fix. the pinion angle of course, and improveing caster better than the 1* the factory gave, 1* works, but a little more, say 4-5* is soo much better.

 

[tfdcruiser]

You could still add to the caster angle by positioning the perches accordingly so they are not quite parallel.

controlling warpage would be a matter of short welds with adequate cooling time. I think you would really need to drain the oil out but you may not need to fully disassemble the axles.
I would probably take them all the way down though and do all my final welding on a table with a jig to hold it in place. I just think that cutting that tube straight with a pipe cutter and turning it there would be much easier and just as accurate than grinding at the knuckles, plus even if I did it the traditional way I would probably truss/gusset the axle tube any way to make it bombproof. I do appreciate all the other observations so keep them coming if you have something to add. Thanks, Don.

 

[RHINO]

sure you could, but your original Q mentioned using the original perch to align the new one for correct (and stock) castor. plus with the traditional way you get to replace the stop steering stops with some custom beefy ones since you'll be cutting them off anyway. and then not needing to make and use a jig seems way easier to me but, if you do it your way maybe you can source some tubing that would make a nice sleeve, that would help cut down on some of the aligning and maybe even a jig.