Kubota L48 TLB stabilizers / outriggers help

[teabor]

What happens if you raise the machine with the dipper/boom and then lower the outriggers? Will the outriggers then support the machine?

Yes. The outriggers will support it.

 

[dfkrug]

Yes. The outriggers will support it.

So, to be clear: you can raise the tractor off the ground with the boom/dipper, then articulate
the outriggers fully from full-up to full-down, correct?

And when you do that, you do not hear any relief valve sounds?

I saw your video, and you were operating both outriggers independenty with the same result,
correct? It looks like the rod should extend another 6 inches or so before it reaches the end.

How did you test to see if the piston seals were good?

 

[teabor]

So, to be clear: you can raise the tractor off the ground with the boom/dipper, then articulate
the outriggers fully from full-up to full-down, correct?

And when you do that, you do not hear any relief valve sounds?

I saw your video, and you were operating both outriggers independenty with the same result,
correct? It looks like the rod should extend another 6 inches or so before it reaches the end.

How did you test to see if the piston seals were good?

Yes, with the tractor lifted up by the boom/dipper I can articulate the outriggers fully down and up. Yes I get the relief sound when its fully extended and fully retracted.

Yes, I was only operating one outrigger at a time on the video. The other side seems like it will lift up the tractor only a bit higher. But still shy of being fully extended.

I tested the piston seal by fully extending the cyl. then removing the hydraulic line from the retraction side of the cyl. I then started the tractor and tried to continue to extend the cly and no fluid came out of the exposed port on the cyl. I did notice a slow stream of hydraulic fluid coming out of the line that I disconnected (this line fed the end of the cyl that would supply the fluid to retract the cyl). This stream would only activate when I hit the relief pressure, it was almost no pressure because I could stop it by plugging it with my finger. I am not sure if this is normal.

 

[teabor]

Here is the Hydraulic circuit for the backhoe and RH stabilizer extend.




Valve block with side view.

 

[teabor]

KEY for the pictures in previous post.

(1) Stabilizer RH Control Valve
(2) Spool
(3) Inlet Section
(4) Outlet Section
(5) Load Check Valve
(6) Lockout Valve
(7) Bridge Passage
(8) Low Pressure Passage
(9) Neutral Passage
P1 : P1 Port
P2 : P2 Port
T : T Port
A3 : A3 Port (To Stabilizer RH
Cylinder)
B3 : B3 Port (From Stabilizer RH
Cylinder)

 

[J_J]

Using a cyl of 2.75 in, and 2500 psi, a theoretical pressure of 14, 849 lbs is computed pushing at 90 degrees which is the max on one cyl.

If the cyl pushes at 45 degrees, the push force is about 10, 500 lbs

However if the angle of push force is about 15 degrees, the push force is about 3843 lbs on one cyl.

With two cyl pushing at that angle, the push force is about 7,686 lbs, which should be enough to raise the tractor rear end.

If the cyl can not extend with a good cyl and a good pump, then there is a mechanical problem.

 

[Stonehaller]

The lockout valve may be sticking. This is a pilot operated check valve that will block both ports of the cylinder if there is no pressure, i.e. main spool centered. It is intended to reduce drift of the cylinder. To check it, put your gauge on the rod side port of the cylinder and extend the cylinder. Pressure should be low as this the return line. Less than 100 psi when the cylinder stops moving. If pressure builds higher than that then the check valve is not opening. Take the lockout valve (item 6) apart and clean it.

 

[dfkrug]

View attachment 420507

What bothers me is there seems to be a check valve in the diagram for the RH
outrigger cyl base A3 (extend), but not the LH cyl. I assume the LH cyl is
just above the RH in the diagram.

The lift problem you have affects both cylinders, so the culprit should be something
that both share. I like STONEHALLER's theory about the lockout valve (check valve),
but I do not see how that can account for both cylinders failing to lift properly.

 

[Dirthog]

Use the boom and arm.

 

[teabor]

The lockout valve may be sticking. This is a pilot operated check valve that will block both ports of the cylinder if there is no pressure, i.e. main spool centered. It is intended to reduce drift of the cylinder. To check it, put your gauge on the rod side port of the cylinder and extend the cylinder. Pressure should be low as this the return line. Less than 100 psi when the cylinder stops moving. If pressure builds higher than that then the check valve is not opening. Take the lockout valve (item 6) apart and clean it.

Hey Guys, I attached my gauge to my stabilizer and ran it through it's cycle. Not sure what to make of it though. Video link below:

Gauge on retraction side:
https://www.youtube.com/watch?v=uwOW1z4p88w

Gauge on extension side:
https://www.youtube.com/watch?v=MZStWNlwufg

Thanks