Loader valve

[SBC]

Good afternoon and Merry Christmas! I have a John Deere 950 with loader and power steering. I'm adding a Brand hydraulics loader valve to replace the existing worn loader valve. I plan to keep the existing loader valve in place and use it for remotes in the future. The Brand valve I've purchased is configured with a power beyond port, an "in" port and an "out" port. I will be tapping directly to my hydraulic pumps outlet. My question is should I use the "out" port or the power beyond port to feed the tractor downstream from the valve? Thanks in advance for your help and consideration!

 

[ericm979]

The power beyond port should feed the downstream valves. "out" would go to the tank.

 

[Harry in Ky]

Your new valve will have three ports connected to the tractor. How many ports does your old valve have, and how are they connected now?

 

[SBC]

Sorry for the delayed response! MERRY CHRISTMAS!

Some pics to illustrate what I'm trying to do.
I installed a manifold with JAC fitting to my pump outlet. This should be the in line in my new valve.

The power beyond outlet on the new loader valve should feed the banjo fitting in the tractor that was connected to the hydraulic pump outlet? (Lower line with blue trace)

I added a quick detach line to the existing loader valve to feed my backhoe. Should I tap into that with the "out" line from the new loader valve?

Gratuitous Pic of my rig chained up for today's snowfall. Merry Christmas

 

[Harry in Ky]

Does your tractor have power steering? That ties in here as well.

As I see it, the loader is (soon to be was) operated with the factory remote valves. The power beyond port of that valve now supplies the backhoe circuit. The hydraulic pump outlet is connected to a hose leading where currently? Would that be the power steering priority valve? Your plan is to route that hose to the new valve "in" port, then the power beyond port of the new valve will go to where this hose goes now? If I have that right, then it looks like a go to me. All that's left is to add a tee on one of the sump connections for the tank port on the new valve.

 

[SBC]

Why do I need to return to the tank? Why can't the loader valve use the in line and the power beyond to the tractor and just plug the "out"?

 

[Harry in Ky]

Power Beyond Option Parts | Cross Mfg.

The power beyond sleeve prevents subjecting the exhaust or return passages and spool seals of the control valve to back pressure.

crossmfg.com

Maybe this will help.

If you look at your current two spool valve you will see it has three lines. That's the way any series plumbed open center valve should be. If you add another valve in series with with you now have it should also be done that way. When you operate the valve, oil flows out to whatever, and oil return through the other work port. That oil returning should have a pathway to sump, not be forced into the next valve in series. Hydraulics 101.

In fact, your backhoe valve should be as well, but apparently isn't. You've been lucky there so far.

 

[K5lwq]

The Backhoe most likely is the last valve in use when it is hooked up therefore does not use Power Beyond but a tank port. The OP is in no danger using the backhoe.

All other valves up stream and when the backhoe is off will need a tank port so the oil will have a path back to tank when you use that valve.

 

[Harry in Ky]

The Backhoe most likely is the last valve in use when it is hooked up therefore does not use Power Beyond but a tank port. The OP is in no danger using the backhoe.

All other valves up stream and when the backhoe is off will need a tank port so the oil will have a path back to tank when you use that valve.

I don't think so based on his photos. It looks like the power beyond port of the remote valve leads to the backhoe supply line and the return must go to the lift system. At least that's what I got from the pictures. Maybe I'm wrong. Maybe the lift isn't operable with hoe attached? Some are, some not. If it's not used then it doesn't matter.

 

[K5lwq]

You are correct that the remote valve power beyond would feed the backhoe. But the 3pt valve is open center and the backhoe tank line will pass thru 3pt valve to the tank. He should not use the 3pt with a backhoe on.

When the backhoe is off he will use a loop line to complete the circuit allowing the 3pt valve to work.

 

[Harry in Ky]

I'm aware of the loop line, but that's not the point. If the three point is not used while the backhoe valve is connected, then it makes no difference, I agree on that. However I don't know how his hoe mounts. Some backhoes are mounted on the three point, so it's possible to apply a load on the lift while the valve is connected, whether it's in use or not. That subjects the backhoe valve spool seals to whatever pressure the lift develops. If that's the case, then he's been lucky so far. Others may disagree, but that's not the way I was taught to do it.

 

[K5lwq]

You are correct except for there is no spool seal. It is a machine fit. If the 3pt was use the way it is plumbed then the back pressure could crack the valve because the the tank port is designed to handle flow pressure only.

We are saying the same thing but most likely the 3pt will be locked down in this case. Either way the OP should not try to use the 3pt when the backhoe is connected.

 

[Harry in Ky]

You can stand by that if you wish, but I have yet to see a control valve that doesn't have at least an O ring on each end. Those are placed there to seal only low pressure, and the area behind them is open to the return passages of the valve body. They aren't expected to be subject to working pressure, as that is, by design, contained by the precision fit of spool to body tolerances. If you disagree with that so be it. You can have the last word.

 

[ptsg]

You can stand by that if you wish, but I have yet to see a control valve that doesn't have at least an O ring on each end. Those are placed there to seal only low pressure, and the area behind them is open to the return passages of the valve body. They aren't expected to be subject to working pressure, as that is, by design, contained by the precision fit of spool to body tolerances. If you disagree with that so be it. You can have the last word.

The O-ring for the spool is there to retain any small leakage that may appear through the close tolerance between the spool and the bore. It also prevents outside contaminants to from getting inside the spool. Some valves also have a wiper.

On my homemade backhoe, I've been feeding the backhoe control valve using the Tank port of the drive control valve ever since I built the machine a looong time ago. I do have separate main relief valve right after the pump. So far, I've absolutely 0 issues with doing it this way. Is it correct? Definitely not but it's just to say that the o-ring on the spools does not see any high pressures at all.

 

[Harry in Ky]

Okay, but I'm not sure how that applies to what this discussion is about.

 

[SBC]

Oh man, I've used the rock shaft a bunch of times with the backhoe on. What is the issue with that?

The schematic shows the out port as optional? Why do I need an outlet to the tank? Not doubting just looking for an explanation. Should I T into where the backhoe returns?

 

[Harry in Ky]

Wow! I can't believe this has gone on this far. Typically, I glance through the day's posts, and look for anything that looks interesting. Usually not much, I might add. Any threads with more than four or five replies I don't even look twice at because they often have a bunch of replies from guys just bickering back and forth over something more than likely not truly related to the subject that started it all. Here I am doing exactly that.

SBC, I have no idea how/where your backhoe valve's supply and return lines connect to the tractor so I have no comment for you at this point. It's entirely possible your system is nothing like the one pictured here.

As for the other subject discussed earlier, it isn't about how the valve is supplied, only about how fluid returns to the tractor and under what pressure.

 

[K5lwq]

I marked your picture of the old loader valve with what I think the connections are. You would want to tee into the port I marked T for tank with a hose from your new valve marked T.

P=Power In
T=Tank
PB=Power Beyond

Hope that clears it up. If not I will try to help.

 

[Noradavis]

Hydraulic control space bar clicker valve for tractor loader usually consist of a spool inside a cylinder which can be mechanically or electrically controlled. The movement of the spool restricts controls the fluid flow. ... Because simple application of electrical power provides control, these valves are used extensively

 

[rScotty]

Good afternoon and Merry Christmas! I have a John Deere 950 with loader and power steering. I'm adding a Brand hydraulics loader valve to replace the existing worn loader valve. I plan to keep the existing loader valve in place and use it for remotes in the future. The Brand valve I've purchased is configured with a power beyond port, an "in" port and an "out" port. I will be tapping directly to my hydraulic pumps outlet. My question is should I use the "out" port or the power beyond port to feed the tractor downstream from the valve? Thanks in advance for your help and consideration!

Hello, I've participated in some hydraulics threads here, but it looks like you are well along. Please do post what you find and the results so we can all learn. .

Before you even get started, it might pay to take a look at a detailed hydraulics diagram in your JD950 Shop Manual. Many - not all - Yanmar products from that era had a Power Beyond outlet as an option. If yours did, it would be located on the rear casting just to the side of the 3pt speed adjusting knob under the seat. On models that had that option, all it required was removing a fitting & replacing one internal sleeve with one for power beyond....same as you do on loader valves to use the PB.

rScotty