Colt Case Ingersoll Garden Tractors

Could you perhaps sketch the hydraulic circuit as it is now? I don't really understand why the lift pressure relief valve would be involved with the pb at all. Maybe it's something else going on and you don't have to go with a splitter valve after all.

I have a single line coming off the power beyond port that I'm dead-heading into a gauge, and that gauge is reading 720.

If my PB sleeve were defective, I think it would completely blow out. Maybe I'd get... 50 or 70 PSI max?

So I think that internally to the TCV that the power beyond is actually coming from the lift circuit. As such it's getting the same max pressure as the lift circuit.

And that makes sense as to the way the 64X series work: Case travel circuits always operate at.. at least 1700? Maybe more? But the power beyond pressure on a 64X is only 1200. With so much less pressure, it cannot be coming direct from the travel circuit. It must be tied to the lift circuit, and then they have the lift circuit relief dialled up to 1200.

That's the way it looks to me right now.

Bob

So you want it stronger than the 600 series?

I'm not sure. I know I want to be able to break out 1000lbs

And my cylinder Id is smaller than the 600 series, so I need higher pressure.

Bob

Why not tighten the relief valve?

Replace the lift relief spring to a stronger one. I have that spare 600 valve I can pull the spring to get the measurements from. I sworn I wrote down the specs for both the 400 and 600 lift relief springs. I'll look around for it. Then you can set your lift relief to your desirement. Now install an inline relief valve to your mid lift. I set my lift relief years ago to 750psi and have had no issues. My hh34 3 point needed it when I make a 3 point boom pole. The lift cylinder has been fine. With an inline relief to the mid you can set it to a much lower setting. Now you will have full control of your loader relief. The lift circuit does control the pb relief. I also belive if you have the lift in float the psi will increase on the lift circuit when loader valve changes.

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I'm going to have to do some thinking about what everyone has posted. I have an extra TCV from my old 442, I can disassemble its lift relief and get a good sense of what spring I'll need.

@Jancoe where in the circuit for your mid lift did you locate your extra relief valve? It seems like I'd have to put relief on both the extension and retraction ports... Am I missing a simple way that a single relief valve can protect both sides of that cylinder?

Bob

At this juncture I can go one of two ways:

I can go the proportioning valve route:

1. Undo what I've just finished, pull out the new power beyond sleeve and it'll put the TCV back as though nothing happened.
2. Bolt in the new proportioning valve next to where my selector valve is currently at, and re-pipe pressure supply line up to it. I've already tested the approach, I know it works.
3. Pipe in from the "primary" port of the proportioning valve back down and into the TCV.
4. Pipe in from the "secondary" port down and over to the new pressure line I just installed.
5. Re-mount my existing selector valve, because the proportioning valve is going to "shove it" to the left.

Or I can go the power beyond route, and "finish what I started":

1. I think that I could actually just disable the lift circuit relief altogether, if I just crank the screw in fully tight. In that case the only pressure relief would be the travel circuit relief, so the whole valve/system would just have a single relief setting, currently around 2100 psi. Tomorrow I'm going to try that and do a pressure test to confirm.

It seems to murky of how exactly i could install pressure relief into both of my TCV lift work ports. Therefore I'd have to strengthen all the components on the lift circuit to get them rated for 2100 or higher:

2. Replace the deck lift cylinder with one that has the same stroke and strength and is rated for at least 2100 psi. I'm guessing I'd have to cut down an existing cylinder because 3" stroke is going to be an oddball. (Isn't it a 3 inch stroke?)

3. My current selector valve and its piping (for my 3 point hitch) is only rated for 1000 psi. So I'd have to replace that selector valve the piping to it.


The proportioning valve route is a little more clear and defined, so a little more appealing to me at this point.


Thoughts?

Bob

Edit: I guess I do know how to put in a relief valve. I think I could install a single new pressure relief valve ($70 after shipping) and put a tee in both lift circuits, each with an outward flow-only check valve, with each line leading to the single relief valve. The check valves ensure that the pressure from either of the two lift lines can't cross bleed the other. It'll cost $70 in cash, I have to do some piping, and I'd have to manufacture the two inline check valves. I guess it's easier than redoing both the cylinder and the selector valve?

Bob

All right, while I've been sleeping I've been scheming.

And assuming that blocking off the lift circuit pressure relief behaves as I expect, I have decided to manufacture the custom component that I need in order to provide pressure relief to both ports of the lift circuit.

I'm going to build a "dual isolated-port relief valve with an integrated tee at the relief outlet."

More details to follow.

So since I'm disabling my lift circuit's built-in pressure relief valve, I need to install a pressure relief valve after the work lines have left the TCV body.

It has to be settable to around 600 psi, Case lift circuit factory specs.

It should have dual ports, so that I can hook it into both work ports of the lift valve, so that either port can have its extra pressure vented/relieved

But those dual ports must be isolated from each other: They must each have a check valve so that oil can ONLY flow out of the work lines, through the pressure relief valve, and ultimately into the tank. Without the isolating one-way check valves on those ports, oil could just flow out of work line "A", into our new device, and then flow right back into work line "B". That would allow pressure to equalize between our two work lines, so our lift cylinder or whatever would no longer work.

The vented oil has to be routed to the tank, so it has to have an output fitting that is connected to "return-to-tank".

The last part is optional, but allows for easier installation: If I give this device two "return-to-tank" ports that are internally connected to each other, then I can use this device as a tee, and save the hassle of having to cut in a new tee somewhere in the return-to-tank manifold. In my case, my power steering return-to-tank line is connected directly to a fitting on my return-to-tank manifold. I'll disconnect that hose from that fitting and connect it one of the fittings on this new device. Then I'll run a new hose from the other return fitting on this device up to the now open fitting on the return-to-tank manifold. So now my ps valve will send its return-to-tank oil into this new device, which will just pass straight through into the new hose, which leads right back where it needs to go, into the "return-to-tank" manifold. So we use our new device as a tee, enabling us to connect two devices to a single return-to-tank manifold fitting.
Here's the basic layout of how it will be hooked up. It'll have 4 JIC 6 fittings, two "protected"/inlet ports and two "return-to-tank" ports. It'll have a standard style pressure relief adjustment screw.

To install it, I'll put in a new tee in each of my lift circuit work lines. Then run lines from those tees to the two inlet ports on this device.
As I mentioned, I'll reroute my power steering valve's return line from where it's attached now to one of the return-to-tank ports on this new device. Then I'll run a new 1/4" hose from this device's other return-to-tank port up to the now open fitting on the return manifold.

So any pressure in my lift circuit lines greater than about 600 psi will trip this device's relief valve and safely bleed off into the tank.

I could buy and pipe in multiple relief valves, at a cost of around... $250? Plus a real rat's nest of extra lines and fittings, for which there is NO ROOM. It's bad enough that I won't even attempt it.

But I already have the block of steel to machine this out of. I can purchase or make the 1/4" NPT x JIC 6 fittings. I already have some random extra ball bearings and springs that I can find something to make two workable check valves. And I have an extra non-holding TCV valve from which I can cannibalize the relief spring, ball, and adjusting screw.

I do need to buy or make a 1/4" NPT plug.

Then I just drill a series of holes, and tap 6 different holes,
Then put it all together, and Voila! I have a shiny new

Dual Isolated-port Pressure Relief Valve with Integrated Tee at the Relief Outlet.


I'll take pictures, and report on how well it works.