Hydraulic issue with home built log splitter

Hi guys. I'm new to this community, and I"m not sure if I should be posting this here, or in the Tool Talk forum. Hope it's ok here.

I just purchased a 1975 Ford 4000 SU, and it came with a few implements. One is a home built log splitter that runs from hydraulics. The splitter was running ok for a few logs, but now after raising the ram, and returning the control to the neutral center position, the tractor stalls immediately. It doesn't seem to struggle, or lug the engine while raising or lowering the ram, even when splitting wood. Just instantly stalls when returning to center, and only from the raising stroke.

The setup is:

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* Ford 4000 SU (1975)
* Ford 735 series FEL with a fan pulley mounted hydraulic pump (19 gpm or 14 gpm, not sure yet)
* There's a diverter valve mounted before the FEL controls, which allows me to divert the hydraulics to two quick couplers for implements.
* The hoses from the quick couplers go to a "omaha brand" (D2?) control valve for the splitter.
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I've taken the control valve off and popped out the spool. It looks in good shape - no scoring etc, and I didn't seen any dirt or goober in there to speak of.

One other potentially useful bit of information is that I did change the filter on the hydraulic reservoir a couple of days ago, but I ran the loader for 15 minutes afterwards, as directed, and didn't notice any issues.

I'm a total hydraulic newb, so any help would be hugely appreciated. I certainly don't want to keep fussing with this while stalling the diesel engine on the tractor over and over again!

Let me know if there is any other information, etc. that would be useful.

The return line from the splitter is having an issue (probably the coupler at the tractor) preventing return flow to the tractor dead heading the device. Might
also be the valve on the splitter. Jim

What's the best way to diagnose? Just start taking things apart?

I took the control valve apart, and the spool looks fine. When blowing through it, air seems to go where it's supposed to.

I know the return after the diverter valve must be working fine, because it's common with the FEL return and the FEL controls work fine.

Any idea why the dead heading would happen only when returning the control to center from contracting the ram, and not from expanding it? That's where I"m really stumped.

If the splitter control valve works fine, and the FEL controls work fine, the problem must be either:

• 
  a) In the ram itself
  b) in the hoses to and from the diverter to the splitter valve
  c) in the coupler
  d) in the diverter valve

I guess I'll just work through them all, starting with the coupler, then the diverter valve.

i agree with the return quick coupler having a problem not letting oil return to
the tractor hydraulic system. The quick couplers may be too small for the flow. When
you are moving the cylinder either in or out the flow of oil is diverted from one
side of the cylinder piston to the other, but when valve is in neutral all flow has
to return to the reservoir. When you first start splitting the oil is cool and
likely a bit less flow, or the heated oil may have an effect on the poppets in the
coupler causing it to close in one direction.
Cure----New proper sized male and
female coupler; or try reversing the male and female halves of the coupler on the
return hose/circuit.------Loren

When you had the valve apart, when in neutral, did the P (pump port) open to the T (tank or return port)?

That's called "open center", that's what the tractor system is set up for.

Another thing to check is if the hydraulic is flowing the correct direction through the wood splitter's valve. If you are putting pressure in through the OUT port, strange things happen.

It was marked "In" and "Out" rather than "P" and "T", but yeah, in neutral, when blowing through the "In" port, air comes out the "Out" port.

Similarly, the "A" and "B" ports are correctly activated when moving the control.

It's open center, and all is good.

Yes, it is.

Is it possible that the coupler is just "stuck"? The little poppet pin inside the female coupler on the return line is really hard to move when pushing on it with a screwdriver. A hole body oomph is needed to move it. Much harder than the matching one on the pump line.

I don't know how the couplers are measured, but if you let me know, I'll tell you the size. For what it's worth, they're on 1/2" hose.

Well, I have good news, and bad news.

The first is that I managed to get the splitter running from the remotes attached to the 3 pt. It worked great, but too slow to be fun, as expected.

The second is that while I was working, I managed to bump into the flow diverter, and divert the FEL pump hydraulics from the FEL to its remotes. This time, since there was nothing attached to them, it was like an instant deadhead, and instead of stalling the tractor, I blew the seals on the hydraulic pump, and puked hydraulic fluid all over the driveway

Let's hope it's only the seals.

Not thrilled, because the pump is in behind the bucket in a terrible to work place.

You should look for a pressure relief in the system. Without one you may have to lookout for shrapnel when the pump explodes.

A failed hydraulic hose can have a flap of liner act like a one way valve. Possible! Jim

(quoted from post at 15:08:47 08/20/19) Well, I have good news, and bad news.

The first is that I managed to get the splitter running from the remotes attached to the 3 pt. It worked great, but too slow to be fun, as expected.

The second is that while I was working, I managed to bump into the flow diverter, and divert the FEL pump hydraulics from the FEL to its remotes. This time, since there was nothing attached to them, it was like an instant deadhead, and instead of stalling the tractor, I blew the seals on the hydraulic pump, and puked hydraulic fluid all over the driveway

Let's hope it's only the seals.

Not thrilled, because the pump is in behind the bucket in a terrible to work place.

Click to expand...

As previously stated , there has to be a relief valve in an open Center hydraulic system or otherwise something has to give .
Is the valve on the log splitter open Center or closed Center ?

Yes, there is a relief valve on the splitter.

The dangerous part is the diverter valve, which has remotes on one side, and FEL controls on the other. When the diverter valve has the remotes chosen, and there is no implement plugged into the quick connectors, the system is effectively deadheaded by design, as far as I can tell. Pretty dumb.

It's compounded by the fact that the diverter valve moves quite freely, and is mounted next to the FEL controls, and easy to bump.

I'm considering the issue with the splitter on hold, pending getting the pump working again, and a new quick connector. How do I measure the size of quick connector i need?

There should not be a return line hooked to the remotes. In a best case scenario, there would be a non pressure return, dumping directly into the sump.

you stated it works both directions as long as it isn't in neutral, that means you have flow thru the pressure and
return lines coming from the source ie tractor,your problem acts as if it is in the splitter valve, simple test uncouple
the return line from the tractor remotes remove the quick coupling that way you have an open flow, place the open end
into and secure it to the filler location of the hydraulic reservoir make sure whether it is the loader or tractor that
is used being if you have an auxiliary pump, then try operating it and see if still stalls when returned to neutral,
still something doesn't add up about the plumbing, the tractor remotes and loader should have a relief valve or share
one, if so your tractor remote valve relief if operating correctly would open before stalling the engine even if the
splitter valve failed, even though simple try this test at you own risk

Yes, that seems to be what it does. The sump is in the loader frame, and it's teed directly into the sump.

(quoted from post at 19:54:09 08/20/19) you stated it works both directions as long as it isn't in neutral, that means you have flow thru the pressure and
return lines coming from the source ie tractor,your problem acts as if it is in the splitter valve, simple test uncouple
the return line from the tractor remotes remove the quick coupling that way you have an open flow, place the open end
into and secure it to the filler location of the hydraulic reservoir make sure whether it is the loader or tractor that
is used being if you have an auxiliary pump, then try operating it and see if still stalls when returned to neutral,
still something doesn't add up about the plumbing, the tractor remotes and loader should have a relief valve or share
one, if so your tractor remote valve relief if operating correctly would open before stalling the engine even if the
splitter valve failed, even though simple try this test at you own risk

Click to expand...

That's a great idea for a test. When I get the pump running again I'll try this.

Just to clarify, it works both ways, as you said.

It works in neutral when I start the tractor, with no noise, weirdness or complaints, from either the valve, or the tractor engine.

It has no issues after returning to neutral from a down stroke of the ram. Again, no noise, weirdness or complaints from either the valve, or the tractor engine.

The only time there's an issue is when returning to neutral from an upstroke of the ram, in which case it stalls the engine instantly.

Agreed that the plumbing is dumb. The remotes need to have a relief valve somewhere.

Until I get around to that, I'll put something in place to interfere with the operation of the diverter valve, so that it can't divert towards the remotes without consciously doing so. Maybe a piece of rubber held on with a pipe clamp to stop it moving.

(quoted from post at 19:03:32 08/20/19)
Yes, there is a relief valve on the splitter.

The dangerous part is the diverter valve, which has remotes on one side, and FEL controls on the other. When the diverter valve has the remotes chosen, and there is no implement plugged into the quick connectors, the system is effectively deadheaded by design, as far as I can tell. Pretty dumb.

It's compounded by the fact that the diverter valve moves quite freely, and is mounted next to the FEL controls, and easy to bump.

I'm considering the issue with the splitter on hold, pending getting the pump working again, and a new quick connector. How do I measure the size of quick connector i need?

Click to expand...

The problem is up on the tractor . This diverter valve sounds like an add on and it eliminated the over pressure protection that is supposed to exist between the pump outlet and prior to the first control valve .