Check my thinking

[Clodbuster]

So, I'm working on a Mitsubishi D2650. I have a thread in that forum, if you want to check it out. But, this is a general hydraulics question.
The problem I'm having is that the loader valve is leaking. There's been some monkeying around with it, so it seems to be pretty simple.
Order up another valve, that you can actually get parts for, and be fat, dumb, and happy.
Here's what's got me here... It doesn't leak all the time. And when it does, it pours out of it, with angry sounds coming from it.
Wondering if that's actually my problem? Could it be something in the control valve is going South?
A little more about what they have going on, on this machine. 9 gpm pump. From there it goes into the pressure side of the valve, 2 spool joystick type. On the outlet side of the valve it goes to the control block, which feeds the power steering on it's outlet side, then makes it's way back to the sump.
As I said, you fire up one time, and it does just fine. The next time you get on it, it's pouring everywhere. And you can hear the pressure relief valve working overtime.
Any advice is appreciated. And I will answer any questions, as best I can, to aid replies.
Thanks in Advance!

 

[CalG]

HELP us out

Where is it leaking from? One of the spool control rods perhaps?

 

[3Ts]

The next time you get on it, it's pouring everywhere.

EVERYWHERE??? Does this mean the hose fittings, control rods, cylinder rod &/or ports? What do you mean "everywhere"?

it pours out of it,

And what does pour out of it mean? Is it a fast drip, a stream, or coming out under pressure? How much comes out in xx minutes?

 

[CalG]

Perhaps the drain line from the valve body is blocked. This would allow pressure to build inside the valve that it is not designed for.

Find that line, follow it back to tank, make sure it is free flowing.

 

[Clodbuster]

Ok.... To clarify, it only leaks from the valve. Seems to be leaking out around the spools rods.
The amount is roughly a stream about the size of a pencil lead, that pours off the bottom of the valve body.

CalG, the return line that you speak of comes from the control block on this tractor. Should I just open the line before the sump and let it flow for a while?
I would think that if there is crud in the line, it would make it's way back to the sump. Unless it's before the control valve. But, I doubt the problem would be intermittent
if that was the case.

 

[K5lwq]

When it leaks, does it stop after a bit? When it doesn’t leak does it start at some point? Could it be leaking when the 3pt is trying to raise?

Wondering if the PB hose and tank hose are reversed.

 

[Clodbuster]

When it leaks, does it stop after a bit? When it doesn’t leak does it start at some point? Could it be leaking when the 3pt is trying to raise?

Wondering if the PB hose and tank hose are reversed.

When it leaks it does it from startup until you shut it off. When it doesn't it just seems to seep after a while.
I was wondering the same thing, but lift operation doesn't seem to affect it.

 

[CalG]

Just to be clear. The valve drain is not the same line as system return to tank. Two different lines!

They do both go back to tank however.

Any line that connects to a control or diverter "block" down stream from the pump is NOT the line I am speaking of.

 

[K5lwq]

Interesting. Does moving the joystick make it slower or worse?

If you can get seals for that valve it should stop the leak if the valve body is not busted. It is the blowing over the relief valve that has me concerned. Especially If you only hear that when it is leaking. That would indicate a blockage somewhere or one of the spools is shifting to a point that flow cannot go to a cylinder.

I have a Youli valve that blows over the relief anytime you engage the first spool. The rest of the spools are fine. It is a design flaw in the valve body.

Before I replaced the valve I would want to take some pressure readings at different points to identify if there is a issue beyond the valve.

 

[Dave M7040]

It seems like the basic plumbing is wrong.

The power steering should be top priority for hydraulic flow not the loader.

On most tractors with a single pump there is a priority flow valve right after the pump to ensure Power steering is served first and with a guarantied volume of oil.

Does the new valve have a Power Beyond port? How many ports are on the new valve? 6 or 7.

Dave M7040

 

[Clodbuster]

So, I'm back with pictures....
I've put together a slide show, to show how they have this tractor plumbed currently. Since Dave M7040 brought up it may be plumbed wrong, I thought it might be good to show how it is now.
Since I've owned this tractor for just a couple of weeks, I'm not ruling out that someone took it apart and put it back together wrong. So, if anyone sees something that isn't right please let me know.
I'll post the pictures on this reply, and then do the narration in a follow up reply.

 

[Clodbuster]

Ok. So, as I've said, this is a 9 gpm system. The pump is a Jovang, made in South Korea. The valve is a six port, two spool, joystick type, from God knows where.

In the first picture is the hard piping coming off the sump that feeds the pump. From there hard piping takes it to the pump in the second picture.
From the bottom of the pump, there is a hose connected to the "P" side of the valve. That's pictured in the 4th picture.
In the 5th picture, these are the lines feeding the cylinders on the FEL.

Leading off the 2nd row, this hose is connected to the "T" port on the loader valve.

Next to that is a picture of the control valve, with my finger on the line that came off the "T" port of the loader valve, where it goes into said control valve.

2nd row, 3rd picture, are the pressure and return lines for the power steering valve. Not pictured are two lines that go from the power steering valve to the slave cylinder for the steering linkage.

2nd row, 4th picture is where the return line comes off the control valve. From here it runs down the side of the case, and then loops up.

And that's pictured in 2nd row, 5th picture. This is where the return, goes back to the sump. Right under the fill cap.
Also, in this picture towards the top, is the cap for the chamber for the hydraulic screen.

And last is just a picture of the tractor, just for reference.

If this thing is plumbed wrong, that would make a lot of sense for what it's doing.

Take a look and let me know what you guys think.

Thanks!

 

[Clodbuster]

It seems like the basic plumbing is wrong.

The power steering should be top priority for hydraulic flow not the loader.

On most tractors with a single pump there is a priority flow valve right after the pump to ensure Power steering is served first and with a guarantied volume of oil.

Does the new valve have a Power Beyond port? How many ports are on the new valve? 6 or 7.

Dave M7040

See above please...

 

[ericm979]

Did you post the pics in the Mitsubishi forum? In case someone has a similar model and can verify that your plumbing does or does not look right. You should see if you can find a shop manual too.

It does seem like it's "wrong" to have the power steering after the loader valve- flow to the power steering would vary depending on what you're doing with the steering wheel. My understanding is that on systems with a single pump there's some sort of priority valve that maintains some flow to the steering gear when the loader is being used. That ought to come first in the chain before the loader valve. It could be incorporated in another fitting or valve though.

Does the leaking or "angry" sound (which I'm assuming is the relief tripping) correlate with anything on the steering? Like turning the steering wheel or having the wheels turned all the way?

 

[Clodbuster]

Did you post the pics in the Mitsubishi forum? In case someone has a similar model and can verify that your plumbing does or does not look right. You should see if you can find a shop manual too.

It does seem like it's "wrong" to have the power steering after the loader valve- flow to the power steering would vary depending on what you're doing with the steering wheel. My understanding is that on systems with a single pump there's some sort of priority valve that maintains some flow to the steering gear when the loader is being used. That ought to come first in the chain before the loader valve. It could be incorporated in another fitting or valve though.

Does the leaking or "angry" sound (which I'm assuming is the relief tripping) correlate with anything on the steering? Like turning the steering wheel or having the wheels turned all the way?

When I first got the tractor, this happened, and it just seemed like everything slowed down. The lift was slow, it got hard to steer, the FEL was slow.
Noticed from the leaking loader valve, that the fluid was really contaminated. So, I drained everything, and cleaned the screen, and refilled with new hydraulic fluid.
I know that a lot of people here, don't like 303. But, that's what they call for.
After changing the fluid, things are better, but still have the leak. I don't seem to have the problem with the steering though, when it happens.
But, I haven't had a lot of time on this tractor yet. Trying to fix this leak before I put it to work.
Since parts are kinda hard to come by for it, I don't want to tear things up diagnosing it, if I don't have to.
And yes, I've put pictures up in the Mitsubishi section. Nobody seems to know anything about this one.
Checked on manuals. None in English for this tractor, just Japanese.
I didn't pay much for it, knowing all that. So, I'm just trying to figure things out.
Other than this hydraulics issue, it runs just fine. And, the transmission and gearings are in great shape. It was hardly used by the previous owner because he couldn't figure this out.
But, he also never took it the shop, or tried to work on it either.
As for another valve or diverter for the power steering.... It's possible that there was one on here, but I haven't found any information that says so.
I put this tractor at around 1980's manufacture date. So, I don't know if that was just how they did things or what.
Was kind of hoping somebody would recognize the control valve and be able to tell me more about it.

 

[Dave M7040]

The pictures are helpful..

Take the time to hand draw a simple sketch showing how the lines connect the various components together. The pump, the reservoir, the loader valve and the block for the steering.

Use my attached sketch as the starting point. What I do not yet know is which lines connect to the steel block near the steering.

I marked up one of your photos with two red lines. These two hoses should be going to the same hydraulic loader cylinder. One at each end of the cylinder.
Please check and confirm this is how they are connected.

Dave M7040

 

[Clodbuster]

The pictures are helpful..

Take the time to hand draw a simple sketch showing how the lines connect the various components together. The pump, the reservoir, the loader valve and the block for the steering.

Use my attached sketch as the starting point. What I do not yet know is which lines connect to the steel block near the steering.

I marked up one of your photos with two red lines. These two hoses should be going to the same hydraulic loader cylinder. One at each end of the cylinder.
Please check and confirm this is how they are connected.

Dave M7040

Will have to wait until tonight to verify the lines that you pointed out, and finish the sketch. In the meantime, I can tell you that the block is in line between the output side of the loader valve and the sump.
The actual return line, that goes back to the sump, comes off of the block.