Hydraulic Issue on Kubota L4200

[North Idaho Wolfman]

This is the outlet block:

 

[North Idaho Wolfman]

Was this part off of the pump?
Have you done any adjustment on this valve?

 

[jman31]

I'm wondering if this is the root of your problem.
Was the hydraulic pump off the engine when you got it?
To what extent was it disassembled?

So the front axle was completely removed because the ring and pinion were completely trashed. Also, when the owner took the loader off, he didn't disconnect the quick disconnects, he disconnected the hoses from the cylinders and the loader control lever was sitting on the tractor. It sat that way in a barn for about 12 years. He said he was using it when a seal came out of the case and started dumping the hydraulic fluid. He thinks he caught it before it has a chance to damage anything, but there is no telling. Other than that, the hydraulics were in assembled condition. He replaced the bad seal. I have since disconnected the loader control lever by the quick disconnects.

 

[jman31]

Was this part off of the pump?
Have you done any adjustment on this valve?

View attachment 150183

The only thing I have done was remove the tube coming in the top and look in there while turning the motor over. Also put a little oil in there. As far as I know it hasn't been off the pump.

 

[jman31]

This is the outlet block:

View attachment 150182

View attachment 150181

That's what I thought, but I wasn't sure. I have not messed with that at all.

 

[North Idaho Wolfman]

I have since disconnected the loader control lever by the quick disconnects.

Have you turned the selector on the front of the above block?

 

[jman31]

Have you turned the selector on the front of the above block?

I have not. Should I?

 

[North Idaho Wolfman]

Being that it sat a LONG time, and no telling if there was water in thee system. It could have very easily damaged the pressure relief valve on that block.
But that would not explain no flow or pressure to the PS and GST.

A leak in the suction system to the pump would cause both pump sections to go down.

 

[North Idaho Wolfman]

I have not. Should I?

If you disconnected the loader valve from the tractor, or to just simplify troubleshooting, yes turning the block to 3 point only will be wise.

Do you have the WSM?

 

[North Idaho Wolfman]

For testing you want the valve in the horizontal position.

 

[TheOldHokie]

Ok. I have no idea how or where the selector on the outlet block is or the outlet block, and all my research has just confused me. it's not just the loader that doesn't work. It's the steering and the PTO lift. It's like all of the oil is getting diverted straight back to the case and none is reaching any of the cylinders.

You have two problems.

1. The pump is not pulling oil from the suction line. I am going to leave that for now.
2. The pump will pull oil from a pail but none of the hydraulics work. Lets take a look at that.

You need to understand the operation of the hydraulic system if you want to troubleshoot it. Thee output of the pump is sent to a hydraulic outlet block on the right side of the engine. The selector valve on that block controls where thatflow goes. Since you have a loader you want the slot on the selector to be in the vertical position which sends the oil out the "B" port to the loader valve.

Picture of the block and how it operates below. Make sure the selector is in the vertical position. Follow the hose connected to the "b" port up to the loader valve and disconnect it from the valve. Stick the open end of that hose inyour 5 gallon bucket and repeat your test. The oil sucked in by the pump should be returned via the hose.

Dan

 

[jman31]

If you disconnected the loader valve from the tractor, or to just simplify troubleshooting, yes turning the block to 3 point only will be wise.

Do you have the WSM?

OK, I will try that. and yes, I believe I have a copy of the manual.
I have tried to locate any leaks in the suction side, but even when I draw oil directly out of a bucket nothing works so I figured that kind of ruled out the suction side.

EDIT: Just saw your follow up. I will try that when I get home from work! Thanks so much.
EDIT 2: Thinking back, I removed the loader control lever because it was pumping fluid back into a bucket through that hose, so that may be a good sign!

 

[North Idaho Wolfman]

OK, I will try that. and yes, I believe I have a copy of the manual.
I have tried to locate any leaks in the suction side, but even when I draw oil directly out of a bucket nothing works so I figured that kind of ruled out the suction side.

Is it sucking oil out of the bucket pretty quickly?

 

[North Idaho Wolfman]

Did you try steering when you were supplying fluid from the bucket?

 

[jman31]

Is it sucking oil out of the bucket pretty quickly?

I don't have a point of reference, but I would say it sucked a couple gallons in 30 seconds or less. I could be off on that time though. It just seemed to me that it was sucking pretty good.

 

[jman31]

Did you try steering when you were supplying fluid from the bucket?

Yes. multiple times. There was absolutely no steering.

 

[North Idaho Wolfman]

Yes. multiple times. There was absolutely no steering.

Here is the real complication to this exact system.
The two pumps work in tandem drive and suction but they are 2 separate pumps and even though one pump is working does not mean the other is.
In other words the PS / GST section of the pump could still be cavitating and be air locked.
Also the regulator could be stuck, it has been sitting a long time.

If you would do one more quick test:
Have the suction side all hooked up
Loosen these 2 banjo bolts and put a bucket under each
First banjo bolt is the GST feed it's right on top of the pump attached to the regulator
Second is at the hydraulic outlet block.
Turn the selector to horizontal this will eliminate everything except the three point.
Have wrenches handy for both banjo bolts.
Start it and run it, if you get a good stream of fluid out of either Banjo bolt fitting tighten the fitting while running.
If it's the banjo bolt on the selector, after tightening check three point operation.
If it's the one on the regulator try steering.
If both try both they should both work.

If you get NO fluid flow, do the same exact test from a bucket feeding the suction side of the pump.

 

[Russell King]

@TheOldHokie and @North Idaho Wolfman

I am recalling this solution to a similar situation on a similar tractor - just to remind everyone of that odd solution (a loose blanking plug). Not that I think that would resolve this issue but it is an easy check since he has been wrenching on the FEL valve

Non-functioning hydraulics

Dan, as I'm following you all's advice, I'm getting you want me to get pressure readings from the FEL valve PB and remote valve PB. I'll get those pressures later this morning. Thanks for the explanation about how the reverse flow can be happening. Yes, it's only with the "control...

www.orangetractortalks.com

 

[North Idaho Wolfman]

@TheOldHokie and @North Idaho Wolfman

I am recalling this solution to a similar situation on a similar tractor - just to remind everyone of that odd solution (a loose blanking plug). Not that I think that would resolve this issue but it is an easy check since he has been wrenching on the FEL valve

Non-functioning hydraulics

Dan, as I'm following you all's advice, I'm getting you want me to get pressure readings from the FEL valve PB and remote valve PB. I'll get those pressures later this morning. Thanks for the explanation about how the reverse flow can be happening. Yes, it's only with the "control...

www.orangetractortalks.com

This is why I want him to put the selector in horizontal position and eliminate the FEL valve or FEL plumbing from the equation.