1966 IH Scout broken axle shaft information

Discussion in 'The Tool Box' started by ozyello, Jul 30, 2018.


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  1. ozyello

    ozyello Farmall Cub

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    This thread is being started at the request of a fellow member to provide information to other IH owners. Recently, my stocker Scout suffered a significant stoppage. In the picture you can see the scrape mark of the backing plate and tire marks on the road as the Scout came to a halt. You sharp-eyed Rock Crawlers will note this is not a section of road on the Rubicon, although the Scout had just come from hilly up and downing looking for a stray heifer A close look at the axle shaft end shows about 2/3 of the crossection had rust on it and only about 1/3 was actually holding things together.
    Unusual break in axle shaft, but know how/why it happened. Shaft was machined/turned at Ft. Wayne IH factory out of rod-stock from nearby steel foundryy. Process well known to me- Rodstock shaped from ingots out of their open hearth process. That process requires sprue cutting of contaminants off of top of ingot when cooled. Once in a while, they would not cut enough off top of ingot and a defective seam would occur when the rod stock was shaped. Steel company attitude back in that day was,"If the customer would find such a defect, the would replace that stock of rod for nothing." They were not about to change their process, so the customer had to do their own inspection upon receipt. At that time, it was, usually, eddy current which could catch obvious surface defects. However , tightly lapped defects could pass by and it would take the later ultra-souond technology to catch the internal defects. Often the defects would show up in the rod shaping at the foundry and then be remelted/reprocessed. Sometimes the defect would be found during subsequent machining at a customer, but once in a great while, only a partial seam would form with an almost indiscernible hairline crack on the surface or even tightly overlapped.

    The defect in this shaft made it through the shaping process at the foundry, the machining process at IH and into my Scout. Even though the defect extended almost 2/3 of the cross-section, my Scout spent its first 116,00 miles on paved roads/easy going. However, the last 15,000 miles have been spent beyond sidewalks.on/between my farm, where the intact 1/3 material, finally, gave up.

    Unmagnified visual, clearly, shows failure of that good material occurred in mostly tensile, not shear, with a little bending and compression. Under optical magnification (100 power) or, maybe, having to go to a SEM (scanning electron microscope 1000 power), I could tell you the history of how the defect surface oxidized (rusted) over time versus the progressive failure of the remaining good parent metal.
    It may be important for others to know that this is an uncommon defect and getting a used replacement is an OK idea. . In other threads , friend Bookie Binder,with others has delineated a lot of good information on these Dana/Spicer rear axles. This one from a Dana 27 had the tapered end of the four different types of axle ends. A used replacement is on the way and plan to use the good information on assembly/end play detail from other threads in the repair. OK you rock crawlers can quit laughing now at my modest off-roading troubles1

    Scout with broken axle shaft.JPG close up of axle shaft break.JPG
     
  2. Greg R

    Greg R Dreams of Cub Cadets

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    May we see the keyway side of the shaft also?
     
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  3. scout2000

    scout2000 Dreams of Cub Cadets

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    Thanks for sharing what you have so far. Very educational.

    Probably would have put this in 'IH tech', vs the tools section, as you really aren't discussing tools though.
     
  4. ozyello

    ozyello Farmall Cub

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    Hi Greg, Here are the only other pictures I took so far, but will try to get more and include the keyway area.
     

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  5. ozyello

    ozyello Farmall Cub

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    You are right. I debated about that; I wasn't sure and don't think mentioning the special tool called plywood that i used in front of and under the backing plate to winch the Scout up on the trailer counts for much either. Will try to do better. from here on.
     
  6. ozyello

    ozyello Farmall Cub

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    Here are two more pictures. One of the broken inner part of the axle shaft rotated and the other of the very outer end of the axle shaft still bolted to the wheel.
     

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  7. ozyello

    ozyello Farmall Cub

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    Update: Used replacement axle shaft showed up today, but repair will not start until next week now.
     
  8. ozyello

    ozyello Farmall Cub

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    Sorry for the delay in getting the picture, Greg, Hopefully, you can see that the seam defect ran under the keyway and did not let go when the keyway was machined into the shaft. My experience has been, sometimes the tightly lapped seams let go when machined and sometimes not. The replacement axle shaft got damaged in shipping and the resolution with UPS about that has kept me from commenting further, but promise to do so, especially, about the issue of shimming for end play with the bearings/axle shaft ends that I have.
     

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  9. ozyello

    ozyello Farmall Cub

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    scout2000, I now have an update to this string which is a series of less than optimum results, but may benefit others. Is now the time to put this string over in the General IH tech section, rather than the tool section, before I continue? Please let me know.
     

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