BH75 Piston broke, twice! Design problem??

[Volnavy]

I jost bought a L3400 HST with FEL and BH. I now have <20 hours on it and probably only 2 on the BH. I dug out two stumps about three weeks ago, then started on a 4' deep ditch. My father-in-law got about 15 feet of it done one day but it was too muddy and we waited until it dried out.

About 15 minutes into it, the dipperstick would not extend completely. I got out looked at it and noticed the piston was bent. We pulled it all in to go home and it snapped. Kubota got a new one in the next day and I put it on. It rained again so today was the first day I got back at it. About 20 minutes into it it would not extend, and I noticed it was bent again.

This is a new design but I am really suprised this would happen. Has anyone else had the problem? I'm not sure what is causing it. I'm just digging a ditch in 2 foot topsoil on 2 foot of clay. It must happen when I am pulling in, because that would put it under compression, which is how it would have to fail. I would also think it would have to happen when it is nearly alll the way in because that would make it extended the most.

Anyway, I'll call the dealer on Monday. What can they do for me? Keep giving me new cylinders? Would they consider a larger cylinder or would that just over stress another component? I'm starting to think "lemon" and do not want to go to a 3pt BH.

Maybe they should just trade me our a larger machine /forums/images/graemlins/wink.gif

 

[tractorman]

I have had to replace cylinders for BH90 owners due to bending and breaking. Someone at Kubota needs to kick the chief backhoe cylinder designer in the $@#%(@ !

 

[Henro]

Maybe I should reduce my lust level for the BH75... /forums/images/graemlins/shocked.gif

I can report that I have A LOT of hard hours on my BL4690A 3PH hoe, trouble free except for one hose failure...lots of digging, stump pulling, etc.

Curious why the cylinder would bend...seems like it two possiblities would be either defective run of cylinders (weak rods) or some kind of binding that causes the cylinder to feel a bending moment rather than a direct push, as it is extending.

Please keep us updated! Be sure to stress you were not abusing the hoe when the problem occured. Sorry to hear of your troubles...

 

[tinytractors]

I think that Ramon49 would love this thread... /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

Pete.

 

[PondFish]

<font color="blue"> Anyway, I'll call the dealer on Monday. What can they do for me? Keep giving me new cylinders? Would they consider a larger cylinder or would that just over stress another component? I'm starting to think "lemon" and do not want to go to a 3pt BH. </font>

Ouch... I'm new to all this but this concerns me. I'm about to get a B3030 with the BH75.

Sorry for the bonehead questions but.. . From what I could tell from the B3030 it was connected via a 4pt quick connect to the subframe. Does the L series require a different subframe for the BH75? I thought the BH90 was the BH matched for the L series?

Are there running problems with the BH75s?

Thanks

 

[AntrimMan]

Volnavy,
Please beg or borrow a camera and post a close-up photo of the failure area and another, zoomed out a bit, of the hoe, inquiring minds want to know where this is happening.

Tinytractors,
if you would please, what is the approximate vintage of the BH90's you have replaced cylinders on?
Do you have any photo's to post?

Thanks,
Martin

 

[AntrimMan]

OOPS, the TINYTRACTORS question is aimed at TRACTORMAN,
sorry, my fault, won't happen again.
Martin

 

[JerryG]

I don't know what your digging style is, but the closer you dig to the unit, the higher the chance of bending a cylinder. I have seen many that have bent cylinder that way.

 

[tractorman]

Unfortunately, the broken and bent cylinders are long gone so I can't post photo's. I can tell you that they were for backhoes sold in 2003. Kubota has since updated the bucket curl cylinder rod with a replacement rod 10 mm larger in diameter. Hopefully that is enough to remedy the situation.

 

[Volnavy]

I'll post pictures tonight.