L2350DT Hydraulic Problem 3-PT Shakes

[mcnuttja01]

Everything as normal except your comment on the lowering speed valve. You start by saying valve is open and then you say it won't lower unless you open it. That is contradictory. Was the test run with the lowering speed valve open or closed? It should be run with the valve open.



Need a much fuller description of this test. What happens at each of the first three positions.

Dan

I tested and the link is below. With the speed control open, raising the 3pt, it will not hold its position and shakes. https://photos.app.goo.gl/uzwqk3c7jkKWQndv6

Jerry

 

[mcnuttja01]

Just to be sure you know about the 3PH speed control knob…

When you turn it fully one direction there is a locked position that will hold it in that position and it will not move down at all unless there is some leakage in that valve.

I agree with @North Idaho Wolfman in that your control lever moves a LOT more than I would expect it to move. Has it always moved that far back?

I tested with the speed control fully open, video below. The length I am having to move the raise the Position Control does seem further than it did a couple of months ago. I only have a few acres so it doesn't get used much, maybe a 100 hrs a year.

 

[TheOldHokie]

I tested with the speed control fully open, video below. The length I am having to move the raise the Position Control does seem further than it did a couple of months ago. I only have a few acres so it doesn't get used much, maybe a 100 hrs a year.

The lowering speed vàlve does just one thing. It chokes off the hydraulic path that allows the lift to lower
If you close it all the way that path is completely blocked and lift position control vslve cannot do anything to open it. It is not the problem - leave it open.

So with this latest video here iscwhat I think:

Your lift wont hold position becsuse the feedback side of the control linkage Is staying in tje lower position when it should be finding the neutral (hold) position.that matches the position control side.

You have to move the position control lever to the very top to get the lift to start up because the feedback side is not positioned where it should be. Thatcscrews up the internal linkage geometry that controls the position control valve

The lift bounces because the position control side is constsntly fighting the feedback side. The position control commands UP and as soon as that happens the feedback side commands DOWN. At full up that cycle repeats nonstop and the lift position hunts (bounces). It stops hunting when you close the lowering speed valve because it prevents the DOWN half of that cycle from happening.

What all that indicates is something in the linksge is busted. If the feedback rod is intact and you cant adjust the lift behavior you need to inspect all of the lunkage connections on both sides both externsl and internal.

Dan

 

[North Idaho Wolfman]

The length I am having to move the raise the Position Control does seem further than it did a couple of months ago. I only have a few acres so it doesn't get used much, maybe a 100 hrs a year.

I think with what everyone has tested and with this statement.
Your issue lies on here:
And yes that means pulling to cylinder and cover off the top and getting to it.

 

[TheOldHokie]

I think with what everyone has tested and with this statement.
Your issue lies on here:
And yes that means pulling to cylinder and cover off the top and getting to it.

View attachment 127882 8

Or possibly a few of the parts outside that circle. I think I would have a good hard look at 120, 150, and 40 through 60 before popping the top.

Dan

 

[North Idaho Wolfman]

Or possibly a few of the parts outside that circle. I think I would have a good hard look at 120, 150, and 40 through 60 before popping the top.

Dan

100% agree!
A sheared roll pin has been the bane of many a troubleshooting dilema!

 

[mcnuttja01]

Thanks to all of you, I really appreciate it. I checked the external parts a couple of days ago and all seemed to be functioning. The roll-pin #150 is in-place.

Looking at the diagram of the Feed Back Lever I think I understand how it function, but would like to verify.

I see the device as a fulcrum. Part 240 is a fulcrum point for part 10. The Position Control moves the fulcrum one direction via part 20, while the Feed Back Rod moves the fulcrum the other direction via part 100.

Part 100 is attached to the Feed Back Rod with a pin through part 140 and 110.

Questions:
1) If I remove pin 150 and completely disconnect the Feed Back Rod mechanism, then reinsert shout rod 110 turn? If so any idea how far? If it spins completely around, would that indicate it has become disconnected from the Fulcrum Rod ?

2) If I remove the Hydraulic Cylinder/Top Case, I assume there is a gasket that will need to be replaced?

3) Any special sealants required when reinstalling the gasket, and the Hydraulic Cylinder/Top Case?

One lat question, in the diagram what do parts 230 and 250 do??


Thanks,

Jerry

 

[PoTreeBoy]

Thanks to all of you, I really appreciate it. I checked the external parts a couple of days ago and all seemed to be functioning. The roll-pin #150 is in-place.

Looking at the diagram of the Feed Back Lever I think I understand how it function, but would like to verify.

I see the device as a fulcrum. Part 240 is a fulcrum point for part 10. The Position Control moves the fulcrum one direction via part 20, while the Feed Back Rod moves the fulcrum the other direction via part 100.

Part 100 is attached to the Feed Back Rod with a pin through part 140 and 110.

Questions:
1) If I remove pin 150 and completely disconnect the Feed Back Rod mechanism, then reinsert shout rod 110 turn? If so any idea how far? If it spins completely around, would that indicate it has become disconnected from the Fulcrum Rod ?

2) If I remove the Hydraulic Cylinder/Top Case, I assume there is a gasket that will need to be replaced?

3) Any special sealants required when reinstalling the gasket, and the Hydraulic Cylinder/Top Case?

One lat question, in the diagram what do parts 230 and 250 do??


Thanks,

Jerry

First, I'm not the expert, but. . .
I'd estimate 100 and 020 should rotate 20 to 30°. Also, your control lever should come through a slot in the tinwork near the fender that restricts its movement to way less than your videos show.

Yes, there's a gasket. If you remove the control valve, there are some o-rings.

Parts 230 and 250 couple the fulcrum (a movable fulcrum) to the actual control valve. The control valve moves in and out for raise and lower, or vice versa. When in the neutral position, the lift stops.

Edit: after seeing post 70, the angles may be closer to 90° max.

 

[mcnuttja01]

First, I'm not the expert, but. . .
I'd estimate 100 and 020 should rotate 20 to 30°. Also, your control lever should come through a slot in the tinwork near the fender that restricts its movement to way less than your videos show.

Yes, there's a gasket. If you remove the control valve, there are some o-rings.

Parts 230 and 250 couple the fulcrum (a movable fulcrum) to the actual control valve. The control valve moves in and out for raise and lower, or vice versa. When in the neutral position, the lift stops.

View attachment 127888

Thank you.

 

[Russell King]

This is from Kubota books dot com and is from a work shop manual for a L2501 since they don’t have your L2350‘s manual

I am making a BIG ASSUMPTION that this is similar to your tractor but I suggest you get to the dealer and see if they can sell or give you a WSM for your tractor. Buy a thumb drive and take it with you and they might give you a digital file for free if you ask.

This shows a linkage very similar to what was shown above and what is connected to what. The same manual has more diagrams and explains things in good detail so you might just read this for information about what Kubota is trying to accomplish with the feedback and controil valve.

 

[Russell King]

And here is the trouble shooting guide from the same manual that is NOT your tractor

 

[mcnuttja01]

And here is the trouble shooting guide from the same manual that is NOT your tractor

View attachment 127897

Ty, I actually have the wsm manual, but it assumes the read has some Tractor knowledge. I don't have much...lol

 

[TheOldHokie]

Ty, I actually have the wsm manual, but it assumes the read has some Tractor knowledge. I don't have much...lol

You have the basics. This may not be exactly what you have but it illustrates the idea.

The position controll lever and the feedback lever are attached to opposing ends of a cross bar. The spool in the control valve is attached to the center.

When either the position control lever or the feedback lever is moved the cross bar pulls or pushes the spool in or out causing the lift arms to raise or lower until the two ends of the cross bar are once more aligned and the spool is centered in the valve.

I suspect you will find something in that mechanical linkage is disconnected and/or broken.

My first step would be to make sure the feedback lever is actually turning the shaft. That roll pin can shear and you lose the feedback side of the connection. You can disconnect the rod and manipulate the lever by hand. With a little close up poking I think you will find your problem pretty quickly.

Dan

 

[mcnuttja01]

Thanks Dan for clarifying. This was mentioned earlier as a possible cause, but I did not understand. I'll check this in just a bit. Once again, I really appreciate the assistance. Ignorance and stupidity are not the same thing.......on this topic my ignorance is starting to fade a little....lol

 

[mcnuttja01]

Thanks Dan for clarifying. This was mentioned earlier as a possible cause, but I did not understand. I'll check this in just a bit. Once again, I really appreciate the assistance. Ignorance and stupidity are not the same thing.......on this topic my ignorance is starting to fade a little....lol

Roll pin is in one piece. When I move the a Position Control, the Feed Back side moves in the opposite direction.

I inserted a small screw driver into hole. With the Position Control in both the upper and lower positions, there is movement and I can move the rod a little with the screw driver. There is a "springy feeling" when I move the screw driver.

I did notice when I was puting the linkage back together, I noticed part #100 moves back into the Hydraulic Cylinder Housing some. I have no idea if this normal, but based upon the drawing it seems like it should stable.

I've attached a video....https://photos.app.goo.gl/4ok6TUuMonF6xDwR7


Jerry