Broken Mount For LA724

[rswyan]

Would be interesting to know if the brackets differ between the ones on our 3240's vs the ones set up as backhoes. I think they are called LTB's?

TLB's (Tractor/Loader/Backhoe)

Have a look at the attached picture which I snagged from the "Features" PDF for Kubota's smallest construction/industrial TLB, the B26.

Consider the difference in how it's constructed (loader mount integrated into - and not separate from - the tractor frame) as compared to a normal CUT with an add-on loader:

 

[PapaPerk]

The 3rd photo showing the cross section of the failure tells an interesting story. Assuming nothing contaminated the break after failure, the rusty/dirty area indicates a hairline fracture that began some time back.

The fracture then propagated into the bracket. This propagation eventually led to total failure of the bracket. The question is what caused the initial fracture. Either the part had a stress concentration in this area, the material tensile strength is below normal, or the bracket was subjected to an overload condition.

Have you ever applied shock loading (impact loading) to the loader when driving forward? A good example would be ramming a stump or large rock.

Good luck with your repairs. A good welding shop could fix this failure by welding back together and then adding scab plates on either side of the failure. However it won't look pretty. A new bracket maybe the best solution.

 

[PapaPerk]

Just noticed you said you are a welder. You'll have it patched up in no time!

 

[PapaPerk]

Is that bracket steel plate that's laser cut or is it a ductile iron casting? Almost looks like a casting but I can't tell for sure.

 

[Grateful11]

The 3rd photo showing the cross section of the failure tells an interesting story. Assuming nothing contaminated the break after failure, the rusty/dirty area indicates a hairline fracture that began some time back.

The fracture then propagated into the bracket. This propagation eventually led to total failure of the bracket. The question is what caused the initial fracture. Either the part had a stress concentration in this area, the material tensile strength is below normal, or the bracket was subjected to an overload condition.

Have you ever applied shock loading (impact loading) to the loader when driving forward? A good example would be ramming a stump or large rock.

Good luck with your repairs. A good welding shop could fix this failure by welding back together and then adding scab plates on either side of the failure. However it won't look pretty. A new bracket maybe the best solution.

Absolutely. The rusted area is evidence of an earlier crack so it was just a matter of time.

 

[rswyan]

Is that bracket steel plate that's laser cut or is it a ductile iron casting? Almost looks like a casting but I can't tell for sure.

Looks to be cast - have a peek at the inside of the remaining upright that is not broken off in picture no. 5 ..... see the indentations from the mold in the casting ?

 

[kcender]

Is that bracket steel plate that's laser cut or is it a ductile iron casting? Almost looks like a casting but I can't tell for sure.

The material is cast steel that is weldable similar to regular low carbon steel.The only difference is that I would preheat it to about 100 degrees before welding and wrap it in fire cloth after welding to let it cool slowly.It has been welded from Kubota with a wire feeder process,probably flux core but I would have to use 7018 stick which is just as strong but slower to apply.I will also add some 1/4 inch plate to the inside making sure there are no straight horizontal seams.I really don't want to start a discussion on welding as these are never ending.As far as the tractor goes I think most of us try to do too much with them at some time or another.I put this on here as a matter of interest for viewers,not to complain.I was using the tractor too hard obviously and this is what happened.It will get fixed and life goes on.It just reinforces my belief that in hindsight I should have spent my money on an actual backhoe or at least a TLB but I guess this is how we learn.Hindsight is 20/20

 

[mainegoatman]

I put this on here as a matter of interest for viewers,not to complain.I was using the tractor too hard obviously and this is what happened.It will get fixed and life goes on.It just reinforces my belief that in hindsight I should have spent my money on an actual backhoe or at least a TLB but I guess this is how we learn.Hindsight is 20/20

I feel your pain , on the other hand thanks for posting this, I learned something here.

 

[Chilly807]

I just wanna say your tractor looks great for having 530 hours on it Very clean looking for that amount of hours. On my old B, the rubber mat on the floor board had a whole worn it at 50 hours. Your mat looks like its never been stepped on.

I hope you and Kubota/dealer can work out something positive.

Do you remember the John Deere trade-in thread with the 2520? His tractor was well taken care of, but I'm afraid he has nothing to compare to the care kcender takes of his equipment. I know him, and I can tell you one thing for sure, if it was abuse, which I'm not convinced it was, it was purely accidental.

We're dealing with a tractor here, not a china cabinet after all. I doubt that moving it with the bucket bottom flat on the ground would put enough twisting torque into the mounting brackets to break the way they did. If anything, I think they should have broken out of the engine block since that is only bolt threads into cast iron.

From what I've seen of broken Kubota parts on TBN lately, I'm thinking they have a potential problem with steel quality in their attachments. The broken backhoe booms and now the loader bracket make me think there's more to this than just use or abuse. Steel shouldn't break like that, without bending first.

Thank God they aren't building bridges.

Sean

 

[Chilly807]

kcender, if you're going to be around later today I might drop in and have a look first hand? I've never seen anything break like that..

Sean