Aux. Hydraulics

yotehunter66 · Feb 25, 2017

How do these compact tractors hydraulics work if they only have two ports? One is the supply and the other the return. Don't most hydraulic valves need a supply a return and a tank line?

Sysop · Feb 25, 2017

I'm not seeing where you have a real question. The bit that resembles a question, you have answered yourself... Two ports on the rear, one is supply, other is return.

Only thing I could add is; which is supply and which is return, depends on which way you move the lever.

yotehunter66 · Feb 25, 2017

I was thinking that for a open center system to work, without a pb, port that one of the lines had to return to the tank. Can that return line feed another open center valve? If not how do these add on aux kits for a lot of the compact tractors work?

Sysop · Feb 25, 2017

The valve itself should be plumbed to the tractor with a supply and return, these are unrelated to the two ports on the back and there is always fluid flowing from supply to return whether you activate the two ports on the rear or not. The two ports on the back are activated by the lever on the valve. Move the lever one direction, flow wants to go out one of the rear ports and come back in through the other. Move the lever the other direction, the flow on the two rear ports reverses.

Sysop · Feb 25, 2017

On another note, there are some implements with only one quick disconnect line, and just an open return. Those you plug into the port of your choice, plumb the open return to your tank, and activate the flow on the used port with the lever.

ovrszd · Feb 25, 2017

yotehunter66 said:
I was thinking that for a open center system to work, without a pb, port that one of the lines had to return to the tank. Can that return line feed another open center valve? If not how do these add on aux kits for a lot of the compact tractors work?

So your question is in regards to the ports on the valve, not the quick couplers at the rear of the tractor??

yotehunter66 · Feb 25, 2017

A little of both. In the case of my Yanmar ex3200 the add on hydraulics for the rear replaces or interrupts the return line from the loader valve. That's why you have to have the jumper hose plugged in for the three point to work. I have a back hoe I'm mounting to my tractor it has a supply and return. If I plug those into the rear remotes than the return line from the back hoe would feed the three point.

ovrszd · Feb 25, 2017

So the tractor supplies the loader, then "Power Beyonds (PB)" to the rear hydraulic remotes, then PB to the 3pt? So if you plug the backhoe into the rear remotes you are expecting it to PB the 3pt?

Sorry if I'm messing this all up.

Pictures would be awesome!!!

yotehunter66 · Feb 25, 2017

Nope you got it in a nut shell. That's how the rear remotes are plumped. That's kind of what I'm missing. Alot of implements like a log splitter for a three point only have two lines. I assumed that an open center valve would feed the other three point unless you move the valve to activate the splitter that would make the three point inoperable until you move the valve back to center.

ch1ch2 · Feb 25, 2017

yotehunter66 said:
How do these compact tractors hydraulics work if they only have two ports? One is the supply and the other the return. Don't most hydraulic valves need a supply a return and a tank line?

The premise of your question is an issue.
Valves have to have 3 ports, most have 4 ports and some have 5 ports.
3 ports; supply, return to tank and 1 work port.
4 ports; supply, return to tank, and 2 work ports.
5 ports; supply, return to tank, and PB. The valve which will be supplied by the PB will have its own return to tank, and its own work ports.

Sysop · Feb 25, 2017

Depends on which valve. The log splitter has a valve too, and that valve must operate in an open center system also. If the valve on the log splitter isn't also open center, the moment you turned the rear remotes on the tractor would bog down and the hydraulic relief would kick in (exactly like if you activate the rear ports with nothing connected). If you turn the remotes on to feed the splitter, but don't activate the valve on the splitter, the 3 point lift should still operate with full power. As you open the valve on the splitter to operate it, it will reduce power to the 3 point lift.

ovrszd · Feb 25, 2017

yotehunter66 said:
Nope you got it in a nut shell. That's how the rear remotes are plumped. That's kind of what I'm missing. Alot of implements like a log splitter for a three point only have two lines. I assumed that an open center valve would feed the other three point unless you move the valve to activate the splitter that would make the three point inoperable until you move the valve back to center.

My Kubota feeds FEL, rear remotes, 3pt in that order. If using any of the first two the 3pt doesn't function.

So when tractor is running and no demand is on the hydraulics it powers the FEL valves and if no use PBs to the rear remotes, if no demand it PBs to the 3pt, if no demand it returns to tank.

In your example of splitter use. If the splitter has it's own valve the rear remote valve lever must be fastened into a power position. This supply power to the splitter valve which controls the splitter. If the splitter doesn't have a valve the rear remote valve lever is used to run the splitter.

So if you are wanting to power a backhoe attachment with it's own bank of valves you would plug into your rear remotes and then power position the lever. This would power the hoe and then you would control it with it's own valves.

I think.....

yotehunter66 · Feb 25, 2017

That pretty much answers my question then. Yes if the implement you have hooked to the rear remotes has its own open center valve then the return from the splitter or back hoe in my case would feed my three point as long as I'm not using the implement.

ovrszd · Feb 25, 2017

yotehunter66 said:
That pretty much answers my question then. Yes if the implement you have hooked to the rear remotes has its own open center valve then the return from the splitter or back hoe in my case would feed my three point as long as I'm not using the implement.

Yes.

yotehunter66 · Feb 25, 2017

Thanks guys. Didn't want to damage a pump or blow a line.

ovrszd · Feb 25, 2017

yotehunter66 said:
Thanks guys. Didn't want to damage a pump or blow a line.

Yep. I think someone mentioned, if you plumb something wrong it'll cause the relief valve to open. there will be a noticeable load on the tractor engine and a squealing sound.

Sysop · Feb 25, 2017

You'll hear the tractor "load up" and go into relief if something isn't right. Damage to the pump is possible if it is ran on relief for a long period, but nothing should simply "pop". The relief pressure is much lower than what good lines in good condition can handle.

hunterj · Feb 25, 2017

This is a basic 3 position block to center valve . Valves come In different variations depending on the need. You have pressure, tank, a and b ports. Fluid flows depending on position of the spool whether solenoid or lever actuated, maybe this helps clear up some of your question.