Broken Mount For LA724

[kcender]

I was using the backhoe and moved the rear of the tractor over to reposition it when I heard a loud snap.I got on the tractor to use the FEL and noticed it was lopsided,looked down and saw the bracket broke clean in two.After going back to the garage I was able to get the loader off.I called the dealer and he said he would come down Saturday to take some pictures and send to Kubota. The loader has a 12 month warranty and the tractor is 15 months old so I am thinking Kubota won't do anything about it after reading other posts on here about similar situations.The tractor has 530 hours on it and most of that is FEL work.I do use it but I don't feel I did anything with the loader that I shouldn't have.When I use the backhoe I lay the FEL bucket flat on the ground so that it will slide when I reposition with the hoe.Maybe moving the tractor around with the hoe is not a good thing to be doing but I thought it was common practice when using the backhoe.After looking at the other bracket I noticed that it has a crack in it as well.You can see from the rust that the broken bracket also had a crack for a while before it broke.I will wait to see what Kubota says but I am thinking I will probably end up welding and reinforcing both brackets.I make my living as a welder so I feel confident in doing this if it is necessary.This incident has kind of left me soured on tractors but that will probably pass with time.I guess tractors are not industrial machines like a real backhoe and are only made to do light work.I never really envisioned something like this happening from the work I was doing with the tractor.Curious to see if anybody else has had a similar problem.The tractor is an L3240.

 

[rswyan]

I was using the backhoe and moved the rear of the tractor over to reposition it when I heard a loud snap. I got on the tractor to use the FEL and noticed it was lopsided,looked down and saw the bracket broke clean in two.

Bummer

I do use it but I don't feel I did anything with the loader that I shouldn't have.

Just curious - what does your owners manual have to say about performing these type of manuvers ?

When I use the backhoe I lay the FEL bucket flat on the ground so that it will slide when I reposition with the hoe. Maybe moving the tractor around with the hoe is not a good thing to be doing but I thought it was common practice when using the backhoe.

On a heavy-duty industrial backhoe maybe .....

I guess tractors are not industrial machines like a real backhoe ...

Correct.

and are only made to do light work.

It's not so much that they are only made to do light work as much as it a case that they are not made to be completely abused ....

Just like any machine, they have their place, and they have their limits .... exceed the limits and you will likely have a problem at some point.

I never really envisioned something like this happening from the work I was doing with the tractor. Curious to see if anybody else has had a similar problem. The tractor is an L3240.

Personally, if I were you, I'd consider myself lucky - the loader mounts can probably be repaired fairly easily.

Imagine if you broken the ___________ (fill in the blank: rear end/differential, transmission, etc. ....)

 

[Wolfy]

I have a full size backhoe. And a 2002 Kubota L3710. In 2003 I bought a Woods backhoe. It will move the tractor around easy. I also lay the bucket flat. But I really don't use the Kubota any different than the full size. So I think you have defective loader brackets.

 

[powerstroke444e]

I was using the backhoe and moved the rear of the tractor over to reposition it when I heard a loud snap.I don't feel I did anything with the loader that I shouldn't have.When I use the backhoe I lay the FEL bucket flat on the ground so that it will slide when I reposition with the hoe.Maybe moving the tractor around with the hoe is not a good thing to be doing.

On any hoe I have ran I always pick up the front bucket to slide it around with the hoe. I can not imagine the leverage you were puting on the loader and i would bet its hard to move with loader on the ground.

On the flip side it don't look that hard to fix. dont worry your not the only guy that learned some hard way. As I have had most of my lessons that way. Good luck

 

[rswyan]

I have a full size backhoe. And a 2002 Kubota L3710. In 2003 I bought a Woods backhoe. It will move the tractor around easy.

The real question isn't whether the BH will move it around ....... but will the machine stand up to having this done to it ?

I can move my tractor (B2910) around with my BH4690B 'hoe too ..... but I don't.

As powerstroke point out: consider the (side) leverage being applied to the loader arms (and thereby the mounts) - ya really think that they were designed to withstand those kinds and types of forces ?

Or are they designed to be operated in a manner which contemplates mostly up/down and front/rear forces, with very little in the way of lateral/side forces ?

 

[crazyal]

I assume you didn't lift your front bucket when you tried to move the tractor, if so I wouldn't expect Kubota to cover it. I often to what your talking about, plant the front bucket so the backhoe can't pull the tractor backwards but I raise it when I want use the BH to move the tractor. I guess you know the weakest link.

I would consider myself lucky that's the only damage you did. You easily could have twisted your loader or damaged the backhoe frame.

 

[crazyal]

By any chance do you have Kubota insurance on it? If so I thin it would cover the damage if the warranty doesn't.

 

[General Lee]

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.

 

[Whitnel]

Well that sucks. When using a backhoe I usually lift the front bucket before moving the machine with the hoe. Hopefully those brackets don't cost too much.

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?

 

[beppington]

OUCH.

I don't have a BH myself, so not knowledgeable about moving the tractor around with it, but your 4th pic, the one showing the crack that hasn't broken yet, makes it look like there's been extreme side forces put on it ... when the bracket's real strength is +90 degrees to that.

 

[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