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