MX5400 hydraulic arm shaft and control rod damage

[mcmxi]

Thanks, Very interesting!
So it's very possible.
My first though that a Quick hitch would mitigate that possibility, but thinking about it more, it could more than likely amplify the side force on that arm at a much squarer angle thus helping to push it off the side.

I don't think this has anything to do with lateral loading, quick hitches or anything else. I think it's a case of the rock shaft working loose during use, most likely because the securing nut and plate weren't installed correctly or possibly due to an incorrect heat treat of the rock shaft allowing excessive elastic or plastic deformation. The OP didn't notice the rock shaft moving off the splined shaft, and when spline engagement was insufficient to support the load on the rock shaft, the splines failed and the rock shaft came off.

How any properly adjusted 3-point linkage would allow the rock shaft to come off due to lateral loading is a mystery to me and frankly not possible without significant damage to other components.

 

[SDT]

Thanks, Very interesting!
So it's very possible.
My first though that a Quick hitch would mitigate that possibility, but thinking about it more, it could more than likely amplify the side force on that arm at a much squarer angle thus helping to push it off the side.

Agreed.

Longer lever arm(s).

Simple physics.

SDT

 

[mcmxi]

Agreed.

Longer lever arm(s).

Simple physics.

SDT

Show a single piece of engineering or mathematical evidence to make a case that the difference is significant rather than your opinion. Simple physics my ass! I doubt anyone has or will ever pay you to solve any mathematical/engineering problem.

The simple fact that Kubota, John Deere and other tractor manufactures sell and approve of the use of quick hitches on their tractors should be evidence enough that your opinion is nothing but hot air. The fact that these companies offers warranties that cover the use of quick hitches should be proof enough. But no, "simple physics" has that covered. What a joke!

 

[GeoHorn]

Show a single piece of engineering or mathematical evidence to make a case that the difference is significant rather than your opinion. Simple physics my ass! I doubt anyone has or will ever pay you to solve any mathematical/engineering problem.

The simple fact that Kubota, John Deere and other tractor manufactures sell and approve of the use of quick hitches on their tractors should be evidence enough that your opinion is nothing but hot air. The fact that these companies offers warranties that cover the use of quick hitches should be proof enough. But no, "simple physics" has that covered. What a joke!

That was unkind at the very least.

Your unwillingness to accept anothers’ viewpoint or opinion, especially your critique that anothers’ “engineering/Physics” belief …without YOUR provision of engineering/physics contradiction or DIS-proof…. makes your response one of obstinance.

SDT expressed fairly clearly how that should be regarded..

…
Ignorance is curable and is not a character flaw. Obstinance, however, is.

SDT

 

[GeoHorn]

Turning with a 3 pt disk in the ground and a back blade angled pushing in reverse will shove the LH arm off of the rock shaft. We have seen this happen 3 or 4 times, usually on a L series.

One customer who does custom landscaping pushed his off 3 times, so the last time I made a 3/16" thick plate that sits on top of the original plate using longer bolts. That was several years ago, customer is still using it with his disk and a seeder.

Whitetiger, It may help DWilly if you’d provide such written or other evidence of that experience to him and his dealer and Kubota.

 

[mcmxi]

That was unkind at the very least.

Your unwillingness to accept anothers’ viewpoint or opinion, especially your critique that anothers’ “engineering/Physics” belief …without YOUR provision of engineering/physics contradiction or DIS-proof…. makes your response one of obstinance.

SDT expressed fairly clearly how that should be regarded..

I would expect this response from you, I've seen it before. I'm not the one making a claim that quick hitches are a pathway to problems so why would I need to disprove something. Call Kubota and ask them if running a quick hitch will void the factory warranty or an insurance claim related to the 3-point won't be upheld. I talked to my dealer and they laughed at the idea.

Kind? I'm not here to be kind or entertain foolish and ignorant agendas. I'm here for facts, truth, and to learn. But if you set yourself up as the know-it-all tractor expert shoveling erroneous information you don't deserve kindness or respect. SDT pushes his anti quick hitch agenda every chance he gets. There is no evidence that the quick hitch had anything to do with the problem in this thread but once again he's pushing the quick hitch is the problem agenda. To say it's "simple physics" shows that he has no evidence to support his agenda.

I learn every day. I learn in my job as an engineer, I learn from forums, and I learn from interactions with knowledgeable people and have no issue with thoughfull and informed information, but that's not what's going on here. This is a witch hunt pure and simple.

 

[NCL4701]

Interesting discussion. With the heim joints in the system it’s a bit difficult for me to understand how the requisite lateral force could be created, but if it has happened (and since whitetiger says it has happened, I’m quite confident it has) my lack of understanding is unlikely to prevent similar damage to my tractor. Will check to see if the upper lift arm retainer is the same on mine, and if it is, fabricating a thicker retainer cap to add on top of the stock retainer will be added to my list of stuff to do.

 

[mcmxi]

With the heim joints in the system it’s a bit difficult for me to understand how the requisite lateral force could be created.

Exactly! If you disconnect the lift arm from the lower link and yank it around, just see how far you have to move it in the horizontal plane to get the lift arm to bind up on the rock shaft. There's no way for a lateral force to be transmitted to the rock shafts unless the heim joint binds up. In order for the lift arm to be in a position that allows the heim joint to bind up, the stabilizer would have to be taken out of the equation.

There's so much misinformation in this thread it's not funny.

 

[mcmxi]

So a picture is better than a thousand words right?

Here's the left side lift arm pushed all the way to the left after being unpinned from the left side lower link. This would be the minimum position required to impart any lateral force on the rock shaft i.e. once the heim joint has bound up on the pin. The second photo taken directly from above shows the position of the stabilizer and lower link pushed all the way over to the left. During normal operation the lift arm is pinned to the lower link so it's not able to get in a position where it can begin to exert a lateral force on the rock shaft. So what does Kubota need to redesign?

 

[GeoHorn]

I would expect this response from you, I've seen it before.

Kind? I'm not here to be kind or entertain foolish and ignorant agendas. I'm here for facts, truth, and to learn.

This is a witch hunt pure and simple.

I’m glad you find I’m consistent.

Correct, you are unkind. In grammar school you were likely graded a Minus-mark on ”Works and Plays well with others.”

Ridiculous summary: You are a confirmed para-normal engineer.

 

[SDT]

Show a single piece of engineering or mathematical evidence to make a case that the difference is significant rather than your opinion. Simple physics my ass! I doubt anyone has or will ever pay you to solve any mathematical/engineering problem.

The simple fact that Kubota, John Deere and other tractor manufactures sell and approve of the use of quick hitches on their tractors should be evidence enough that your opinion is nothing but hot air. The fact that these companies offers warranties that cover the use of quick hitches should be proof enough. But no, "simple physics" has that covered. What a joke!

"I doubt anyone has or will ever pay you to solve any mathematical/engineering problem. "

You think not? Why, then, was I hired as a design engineer by 4 different companies over an engineering career of 25+ years?

I have no dog in the quick hitch issue but it is both intuitively and professionally apparent to me that moving the attachment point of the implement 4" further from the fulcrum will increase any forces applied to hitch components by such implement.

Again, I think that you place far too much trust and faith in dealers and their commissioned salespersons.

I will avoid ad hominem attacks as such indicates an advocate lacking substantive arguments.

SDT

 

[whitetiger]

Exactly! If you disconnect the lift arm from the lower link and yank it around, just see how far you have to move it in the horizontal plane to get the lift arm to bind up on the rock shaft. There's no way for a lateral force to be transmitted to the rock shafts unless the heim joint binds up. In order for the lift arm to be in a position that allows the heim joint to bind up, the stabilizer would have to be taken out of the equation.

There's so much misinformation in this thread it's not funny.

You can just keep telling yourself that, by the way, look at the pictures in the first post. It cant happen, it cant happen, it cant happen.

 

[whitetiger]

Whitetiger, It may help DWilly if you’d provide such written or other evidence of that experience to him and his dealer and Kubota.

I have it on good authority that Kubota knows. It has also happened to Red, Blue and Green tractors, it does not seem to matter whether a cap is bolted on or a snap ring is used on the rock shaft.
It is not all that uncommon on tractors used to pull a terracer in hard or rocky soil.

 

[mcmxi]

"I doubt anyone has or will ever pay you to solve any mathematical/engineering problem. "

You think not? Why, then, was I hired as a design engineer by 4 different companies over an engineering career of 25+ years?

If that's true, you should be ashamed of yourself! You're being disingenuous and you should know better.

 

[mcmxi]

You can just keep telling yourself that, by the way, look at the pictures in the first post. It cant happen, it cant happen, it cant happen.

I'm not doubting that this happened to the OP's tractor, only the ludicrous explanations. It's the lateral loading, it's the quick hitch etc. Blah, blah, blah.

Explain how the rock shaft sees any lateral loading with a properly set up 3-point.

 

[mcmxi]

I have it on good authority that Kubota knows. It has also happened to Red, Blue and Green tractors, it does not seem to matter whether a cap is bolted on or a snap ring is used on the rock shaft.
It is not all that uncommon on tractors used to pull a terracer in hard or rocky soil.

So you have it on "good authority" ... but Kubota, John Deere, New Holland and other companies don't have the engineering ability or foresight to make such a simple upgrade ... but you do?

I stopped by the Kubota dealer yesterday and asked the lead mechanic if he's seen such a thing. He's been with Kubota for decades and his response, only on older B series tractors and rarely on those. But what does he know. He's not a forum "expert".

 

[whitetiger]

only on older B series tractors and rarely on those.

But you said that it cant happen????????????

 

[loggin]

So you have it on "good authority" ... but Kubota, John Deere, New Holland and other companies don't have the engineering ability or foresight to make such a simple upgrade ... but you do?

I stopped by the Kubota dealer yesterday and asked the lead mechanic if he's seen such a thing. He's been with Kubota for decades and his response, only on older B series tractors and rarely on those. But what does he know. He's not a forum "expert".

Out of curiosity, did the mechanic happen to mention how the damage was caused on those older B series??

 

[mcmxi]

But you said that it cant happen????????????

Learn to read. I never once stated that it can't happen, merely questioning the theories of how it happened.

 

[mcmxi]

Out of curiosity, did the mechanic happen to mention how the damage was caused on those older B series??

Yes, he stated that on older B series the rock shafts would occasionaly work themselves off the splined shaft through up and down motion, vibration, poor fit, incorrect manufacturing etc. He only saw a few with the older B series but hasn't seen it happen for a while and couldn't recall ever seeing it happen to any current models.