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Cat 12F differential crack

Discussion in 'Motor Graders' started by Onfoot, Apr 25, 2021.

  1. Onfoot

    Onfoot Well-Known Member

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    Here's the latest on Hanna and the crack. I spoke today with a fellow who is supposed to be one of the best welders in the Territory at Mobile Maintenance (https://www.mobilemaintenance.ca/), showing him the photos and discussing options. He said that re-welding would be a crap shoot. It might work, but would just as likely it worse. He also noted how welding cast steel, unless done appropriately (which he explained at some length), would almost inevitably leave small imperfections that would lead to (in my case) leaks. From looking at the photo, he had no doubt that the weld was not appropriately done. Sigh.

    He suggested going with an epoxy, but was unable to suggest any in particular. He also suggested grinding the exterior weld to flatten and make for a better surface to bond the epoxy. I was concerned about weakening the crack. He did not see that as an issue.

    Which leads to the conversation I had with a representative for Belzona. I was asking especially about Belzona 1161. The rep said that Belzona would have been perfect IF it had not already been welded. The Belzona would not, he assured me, adhere to the weld. In time, it would just peel off. His suggestion was to check out a competitor: Defcon Tungsten metal epoxy. He also said that I should use a heat lamp to sweat out the oil in the cast steel pores. I.e., clean with brake cleaner, then put it under a heat lamp for 3-4 hours. Repeat at least a couple of times, leaving the heat lamp on overnight for the last time. Oh yeah, and to be sure to thoroughly rough up the previously applied epoxy on the inside of the diff.

    Tomorrow I am going to call the technical support lines at Loctite, JB Weld, Permatex and Defcon and see what I can learn. I'll let you know what I find out.
     
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  2. Onfoot

    Onfoot Well-Known Member

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    I might add that the minimum amount of Belzona one can purchase is a 1kg container--running about CDN$440.00...

    Jonas302, not sure what is the RTV you suggest slathering all over the outside...
     
  3. Jonas302

    Jonas302 Senior Member

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    Something like pematex ultra black not really the intended application but its flexible and sticky, easy to apply I've seen it used on a cracked diff of a 140G
     
  4. Onfoot

    Onfoot Well-Known Member

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    Hmmm. This might just be the ticket--if it will adhere to the interior surface. If I rough up the epoxy coating and sweat the oil out of the cast iron, it should adhere, I should think...
     
  5. Bluox

    Bluox Senior Member

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    Dream on.
    Bob
     
    old-iron-habit likes this.
  6. Coaldust

    Coaldust Senior Member

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    Onfoot,

    Thanks for the update and sharing the response from Belzone. Good to know.

    I realty think any RTV would turn to goo inside an compartment subjected to submersion in gear lube.
     
    59 North and skyking1 like this.
  7. Vetech63

    Vetech63 Senior Member

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    Why not try running a heavier viscosity oil and see if the leak improves? The results may point you in the proper direction for a more permanent fix. I personally would want to know if the crack is opening up under load or not.
     
  8. Onfoot

    Onfoot Well-Known Member

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    Thanks, Vetech63. I'm running synthetic 75W-90 gear oil. When it's below -20C (let alone below -30C), heavier viscosity can be a serious issue. So far as I can judge, the crack is not opening under load. With cast iron, there really is no flex. If it was opening, it would be failing utterly, I should think.
     
  9. Bluox

    Bluox Senior Member

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    That housing is not cast iron but is cast steel and is not that hard to weld.,
    it will not heal itself and no amount of goop will stop the leak.
    The pictures of the old welds are of a **** poor job.
    there will be a fair amount of side pressure because of the ring gear side thrust and it should be properly welded.
    Bob
     
  10. Onfoot

    Onfoot Well-Known Member

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    I am grateful for your thoughts, Bob. And I take your point about not being cast iron, but cast steel. I am going to call the Caterpillar metallurgy folks tomorrow in Mossville, IL and see if they have any wisdom. They will at least know the precise carbon % of the diff, I hope. For what it's worth, I am not a welder. And one of main welders at our local heavy equipment metal fabricating outfits told me that it he would be happy to weld it, but thought it would be a crap shoot if it worked and that it might make it worse. Perhaps he is wrong, but I cannot risk making it worse. After speaking with a Permatex chemist today, I cannot but think that Permatex Spray Sealant Leak Repair (https://www.permatex.com/products/adhesives-sealants/sealants/permatex-spray-sealant-leak-repair/) on the outside of the welded crack might be sufficient to stop the leak. At the very least, it won't make it worse.

    No argument that the current weld is a **** poor job. But it is what it is. It preceded me by a good many years.
     
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  11. Fat Dan

    Fat Dan Well-Known Member

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    More great advice. Buuut !!!!
    I found some old Bazooka Bubble Gum on my bedpost.... o_O Sorry had to....
    Hows the Hanna coming along ??? ... I'm on pause for today my back is angry with me:mad:
     
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  12. Coaldust

    Coaldust Senior Member

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    Fat Dan,

    hope your back gets better. Thanks for bumping this thread. I agree. We need an update on Hanna.

    I’m OOS, as well. Just choked down the first two tablets of a z-Pac and a couple snorts of steroid spray. The China Flu is trying to kill me. Day10.
     
    Fat Dan likes this.
  13. skyking1

    skyking1 Senior Member

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    I have a friend who posted in another thread about being sicker than sick, and the last thing he said was this thing is for real!
    It was all I could do to keep from saying no **** Sherlock :)
     
  14. Fat Dan

    Fat Dan Well-Known Member

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    No No nothing that bad but it is the worst case of Lumbago;) my doctor's ever seen LOL. Might even say it's terminal not so much that I'm going to die from it ... but I AM going to die with it... o_O.
    I have a photographic memory;:D the problem is, it's on microfiche and the light is real, real dim now-a-days..:rolleyes:
     
  15. Fat Dan

    Fat Dan Well-Known Member

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    Coaldust, I hope your doing better soon:)
    After you Doc clears you

    Ol' family recipe for a Hot Totty: A.K.A Irish sweat lodge.
    4oz. WARM water
    1 jigger of bourbon,
    twist of lemon,
    pinch of ginger,
    1 tbl honey.
    stir well and drink all at once.. Tastes like crap .. then go to bed and cover up.
    you will be socking wet in the morning from sweat and the bed close will be wet from sweat.
    Like an Irish sweat lodge.
     
    Last edited: May 5, 2021
  16. Coaldust

    Coaldust Senior Member

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    Thanks Fat Dan! I appreciate the old family recipe. I’ll give that a try.

    I think it’s day 16, since symptoms appeared.
    The virus has run the course, but now I’m dealing with pneumonia. Good news is, I’m not dealing with any of the damaging Covid lung stuff the clinics are seeing in some patients. Just regular pneumonia at this point. Oxygen saturation is good. Waiting to hear what the Doc recommends next.
     
    Fat Dan likes this.
  17. Onfoot

    Onfoot Well-Known Member

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    Glad to hear that you are on the mend, Coal Dust! Sorry to have missed a few days on the forum and just now learned of your brush with Covid. No small thing! Fat Dan's Hot Totty recipe may be worth a try. Hope that Fat Dan's back is doing better, too!

    Re. Hanna, I am waiting for the arrival of some Permatex Spray Sealant for sealing the exterior of the differential. The inside will be sealed with Glyptol 1201, which I was able to source locally. Challenge now is cleaning the interior of the crack as much as humanly possible from soaked in oil. Will let you know how it goes.

    Yesterday new glass was installed, replacing all the cracked glass in the cab. Doesn't affect how she runs, but she looks much nicer. Will let you know how things go, for sure. Thanks!
     
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  18. Fat Dan

    Fat Dan Well-Known Member

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    Thanks for your kind words Onfoot.; I'm in the same boat having a lot of projects going at the same time but :rolleyes: the one I want to work on is on hold for a moment so it feels like I'm not getting anything done... :)