Backhoe L48 sub frame broke

[messtrap]

Well, I had the frame upside down so it would drain out of the crack. Picked it up with my B loader and what-do-u-know, the good side has water in it because I can see where it is coming out. I now have a battle again with Kubota, more ammunition. The frame also had oil in it, came out of both sides. I hope this is a bad weld so I can go after them again.

 

[skyhook]

The last picture, on the opposite side of the arrow you posted,
you can see where the frame has come apart, it's not level or straight aligned.
It's started to rust and come apart at the weld,
Definitely a defective weld. Kubota should take responsibility on this one.

 

[rbargeron]

......the good side has water in it because I can see where it is coming out.......

There's the proof - poor fit-up and welding. I would think Kubota would take an interest in this defect. For something like that not to be caught at the factory is a potential threat to their reputation. Overall, they are a high-quality manufacturer and if the right eyes see this they will make it right. Meanwhile the take-away is that drain holes are cheap insurance.

 

[bumperm]

Drain holes let water out, but also allow moisture in the form of water vapor in, and with variations in temperature, "breathing" occurs. In practice, assuming the drain hole is properly located, studies show that only a minimal amount of internal corrosion will occur. But also that with a properly welded, sealed structure, no detectable amount of internal corrosion occurs. For corrosion to occur, besides the reactive metal, there needs to be water or water vapor and oxygen - - in a sealed structure, once either have been used up in the oxidation process, no further corrosion occurs.

There's may be several things going on here, and all look to be Kubota's fault, poor material quality or welding, and/or stress corrosion cracking.

I wouldn't be drilling additional drain holes on my Kubota. If properly designed and built without them, they should not be needed. If one does add them, I'd think there would would be no recourse with the manufacturer and little likelihood of them stepping in to cover the modified product.

bumper

 

[rbargeron]

....... If properly designed and built without them, they (drain holes) should not be needed........

That's true, but inspecting for cracks where these are is impossible with the tractor assembled. Drilling holes would eliminate the issue. There's little point in allowing the frame to remain at risk for failure just to preserve the right to make a warranty claim (that may only partly succeed). Unfortunately none of this helps messtrap unless it's seen by Kubota eyes. Let's hope they reconsider and supply a new frame.

 

[messtrap]

Thanks for the input guys, if it wasn't for all the responses I probably wouldn't have found the problem. Battle with Kubota starts again monday morning. I was surprised at the oil that came out first on the cracked side after all the responses on oil and what it does. If it wasn't for the small drip of oil on the good side I might have overlooked it but it left a dirty trail for me to investigate. It gives me hope anyway that I will get the full refund. Pick up the new frame Monday hopefully. Thanks again!

 

[sd455dan]

Hello rbargeron, the tractor has never been driven in water deep enough to even touch the frame. To answer your questions rbargeron, I'll take some pics of the frame tomorrow, it's sitting in the yard and you'll be able to see all the answers to your questions. The frame was fine late fall when I pressure washed it and got it ready for winter. The spring is when I noticed the damage. (No way the pressure washer filled it either, I can't find a crack anywhere. The existing crack I believe rusted after it burst open. Take a look at the pics tomorrow night, Really stands out off the tractor.

I Know this can happen-

my old ford 3000s 730 loader lasted almost 40 years- and then about 3 years ago the lower right loader arm began to bulge at the bottom -a little more the next year .

I thought i was pushing the loader to hard, and then my father in law saw it and said you have water that has been freezing in that arm...
I pulled out a drill and ran a hole in it at the bottom , it took over 5 minutes for all the water to drain out... i pressure wash the tractor from time to time-just like what you stated.

My thinking is that (somehow- bad weld ,porosity??) the pressure washer managed to infuse a welded tube with water.

No new bulging since drilling a drain hole.

Good Luck - hopefully this repair doesn't get to expensive...Or better yet it gets replaced for no cost

 

[messtrap]

I ordered the new frame end of August. Had it in two weeks. Open the plastic and its the wrong frame, right part #, frame looks like its to a B or BX. Dealer orders new frame, again. Was suppose to be in a week ago last Monday. No frame. Kubota then states delivery for last Monday. No frame. Yesterday Kubota states it will be here October 17th, they didn't have the materials to make it. Lets see, 3 months just for the Kubota engineers to look at pics and it will be 1.5 months to get the frame if it comes in. Don't know how much faith I have left.