MX5400 hydraulic arm shaft and control rod damage

[DWilly]

The dealer's first response today was that they have to make the repairs and then submit the warranty claim for approval after.

I said if it's not going to be covered, I'll probably take it back and make the repairs myself. To which they responded, in that case they can submit for pre-approval.

Their initial inspection gave the rock shaft a clean bill of health.

I suggested they take a second look.

Service department at this busy dealership joined everyone else in saying they've never seen this kind of damage.

They expect to submit the claim for pre-approval this week and should have a response by early next week. That's faster than I was expecting, but faster is not always better.

Timing-wise, best case, if it's approved, they order the parts early-to-mid next week.

Meanwhile, a 6" snow surprised us last night and bigger storms threatening next week to further cover up my 1/4 mile driveway. Sigh.

 

[mcmxi]

The dealer's first response today was that they have to make the repairs and then submit the warranty claim for approval after.

I said if it's not going to be covered, I'll probably take it back and make the repairs myself. To which they responded, in that case they can submit for pre-approval.

Their initial inspection gave the rockshaft arm a clean bill of health.

I suggested they take a second look.

Service department at this busy dealership joined everyone else in saying they've never seen this kind of damage.

They expect to submit the claim for pre-approval this week and should have a response by early next week. That's faster than I was expecting, but faster is not always better.

Timing-wise, best case, if it's approved, they order the parts early-to-mid next week.

Meanwhile, a 6" snow surprised us last night and bigger storms threatening next week to further cover up my 1/4 mile driveway. Sigh.

Any suggestion that the quick hitch they sold and installed on your tractor would disqualify you from a warranty claim?

 

[DWilly]

Any suggestion that the quick hitch they sold and installed on your tractor would disqualify you from a warranty claim?

Nope. But since they didn't even notice the obvious damage on the rock shaft, even though they saw the damaged splines on the lift arm, I'm not sure they've given it a whole lot of thought.

 

[whitetiger]

I've never seen one do that, I would say it's got to be a defect of something

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.

 

[TheOldHokie]

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.

Thats interesting. I will keep it in mind. Sounds like something Kubota needs to address.

Dan

 

[PoTreeBoy]

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.

Always the left arm? I can't see what geometry lets the load transfer to the lift arm. Lucky it doesn't break it. I'll have to study next time I'm at the dealer - and they have inventory.

 

[DWilly]

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.

Good info. Usually if I push backward with the blade it's straight, but I have pushed it with an angle a few times.

Thinking back about my earlier complaints to the dealer about slow bucket movement, and their suggestion to lower the 3pt from its high position to alleviate it, makes me think the link may have been damaged for some time, before this last work day finished it off. I guess another alternative would be that there hadn't been damage to the link but the rod just wasn't adjusted properly.

Whatever happens on the warranty, I think I'll follow your advice and rbargeron's advice upthread and add support for the link.

 

[DWilly]

Always the left arm?

The right arm has a different design to keep it attached. It seems like the control rod link isn't strong enough to withstand this force on the left arm.

 

[RCW]

Thinking back about my earlier complaints to the dealer about slow bucket movement, and their suggestion to lower the 3pt from its high position to alleviate it, makes me think the link may have been damaged for some time, before this last work day finished it off.

This is likely a different issue.

If the 3PH is fully-raised, it could cause the hydraulic system to go into "relief", bypassing the system's components. It's a protective measure, and when it does so, can cause other parts of the hydraulic system to not operate properly.

 

[DWilly]

This is likely a different issue.

If the 3PH is fully-raised, it could cause the hydraulic system to go into "relief", bypassing the system's components. It's a protective measure, and when it does so, can cause other parts of the hydraulic system to not operate properly.

But isn't the thing that makes it go into relief the control rod? Is it intended to go into relief at the high point even if the control rod is adjusted properly?

 

[RCW]

But isn't the thing that makes it go into relief the control rod?

Correct - - the feedback rod acts somewhat like a limit-switch to avoid a relief condition when adjusted properly.

Sorry, I missed that in your post.

 

[DWilly]

Correct - - the feedback rod acts somewhat like a limit-switch to avoid a relief condition when adjusted properly.

Got it. Thanks!

 

[TheOldHokie]

But isn't the thing that makes it go into relief the control rod? Is it intended to go into relief at the high point even if the control rod is adjusted properly?

The feedback rod kicks the 3pt valve back into neutral when the lift reaches the top of its travel. When the valve is in neutral the pump flow is being unloaded to tank.

If the feedback rod is miss adjusted and does not return the valve to neutral the pump is left deadheading against the 3pt cylinder. That blocks all flow through the power beyond circuit and causes the main relief to open.

The loader is unable to operate because the power beyond circuit is blocked and both loader inlet and outlet is at full system pressure.

Dan

 

[mcmxi]

The rockshaft moved right, withdrawing from the arm, bending the bolted 150 end plate. It became barely engaged on the splines - and finally failed while lifting the blade, with only the outer ends of the teeth engaged.

The question is what either pushed the left arm to the left or the right arm to the right ?

This is still what I don't get. There isn't much holding on the rockshafts which indicates that they're not subjected to any significant lateral (axial) forces. How is any significant lateral load transferred to either rockshaft given that the lift arm has a heim joint at the rockshaft connection and the lift arm is stabilized for lateral forces via the telescoping stabilizers?

The lift arm would have to be at the limit of its travel to get the heim joint to bind up, which means that the telescoping stabilizer would have to be collapsed or maybe not installed. This is all very odd.

 

[mcmxi]

@DWilly, did you run an implement on the 3-point without the stabilizers connected?

 

[DWilly]

@DWilly, did you run an implement on the 3-point without the stabilizers connected?

Nope. Stabilizers were connected when it was delivered by the dealership last Sept and never modified in any way. They were inspected after the damage and nothing unusual noted.

 

[DWilly]

My right lift arm connection doesn't have this piece.

 

[mcmxi]

Nope. Stabilizers were connected when it was delivered by the dealership last Sept and never modified in any way. They were inspected after the damage and nothing unusual noted.

Weird! If you look at the lift link (arm) and notice the heim joint where it connects to the rock shaft, it would have to be at an extreme angle in order to bind up and exert a lateral force on the rock shaft.

 

[mcmxi]

My right lift arm connection doesn't have this piece.

It's part of the draft control mechanism that I ordered with the new tractor.

I still don't see how the linkage as shown above can be in a position to exert any significant lateral forces on the rock shafts, due in large part to the heim joints and stabilizers. Oh well, I guess the quick hitch is to blame.

 

[North Idaho Wolfman]

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.

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.