Adding power steering and power beyond question.

[etpm]

I posted this in hydraulics but nobody replied so I am trying here.
I have a Yanmar YM2310. Last year I bought a hydraulic cylinder/valve combo made for adding power steering to this tractor. I got or made all the parts necessary to do the job except for the hose and some fittings. The project got put on hold for a while but now I once again have time to finish it. Before I order the hose and the rest of the fittings I would like some advice on plumbing.
The tractor has an aftermarket FEL and the valve for the FEL has power beyond. The hydraulic line that used to go directly to the 3PH was cut and now goes to the FEL valve. From the power beyond port on the valve a hose goes to the line that goes to the 3PH.
I have a flow divider and from that divider the fluid will flow to the power steering cylinder and to something else. The divider can be plumbed before the FEL valve. If plumbed that way the FEL and 3PH will be affected by the reduced flow. If the divider is plumbed after the FEL valve then only the 3PH will be affected. I think the latter scenario is the best way to plumb everything. I could be wrong though.
To maybe make things more clear I will restate things. The output from the hydraulic pump can go to the divider first. Then from the divider the pressurized fluid will go to the power steering cylinder and the FEL valve. Then from the FEL valve power beyond port the fluid will go to the 3PH. OR, the output from the pump can go to the FEL valve first, then from the power beyond port to the divider. Then fluid from the divider will go to the power steering cylinder and the 3PH.
If I plumb the diverter before the FEL it will mean less fluid to the FEL so it will move slower but the steering will work even if I am using the FEL. If I plumb the divider after the FEL the steering won't work if I am moving the FEL but the FEL will move as fast as it does now.
I can raise the engine RPM to compensate for the decrease in fluid if the divider is plumbed before the FEL. I don't usually use the FEL at top engine RPM anyway. Another way to compensate for reduced flow would be to buy and install a hydraulic pump with a larger displacement. However, I have not been able to find one that will fit my tractor.
Opinions?
Thanks,
Eric

 

[ericm979]

Does your loader valve send flow out the PB port when the valve is being operated? Mine doesn't, it all goes to tank. It'd be a bummer to lose power steering when you're moving the loader.

Will the divider always send flow to the steering even if the cylinder is not being moved? Maybe there is some sort of priority valve which will prioritize the steering but allow full flow to the loader when the steering does not need it? I think I'd rather have the loader performance vary than the steering but you might want it the other way.

 

[etpm]

Does your loader valve send flow out the PB port when the valve is being operated? Mine doesn't, it all goes to tank. It'd be a bummer to lose power steering when you're moving the loader.

Will the divider always send flow to the steering even if the cylinder is not being moved? Maybe there is some sort of priority valve which will prioritize the steering but allow full flow to the loader when the steering does not need it? I think I'd rather have the loader performance vary than the steering but you might want it the other way.

My FEL valve only sends fluid out the power beyond port when the valve is in the neutral position. I have decided to keep steering always and live with the slower FEL or higher engine RPM. You are correct, it would be a bummer to lose steering at any time.
Thanks,
Eric

 

[K5lwq]

Definitely put the divider before the loader. Does the divider you bought have adjustable flow rate for the priority circuit?

 

[rScotty]

Definitely put the divider before the loader. Does the divider you bought have adjustable flow rate for the priority circuit?

That is the way that Yanmar did it with their hydrostatic power steering. Before the FEL They used an adjustable divider with a priority circuit. Universal priority valves with adjustable percentage flow plus a relief valve are reasonably priced at hydraulic outlets like surpluscenter.com

I used to have the factory shop manual for the US versions of your tractor & I if I remember correctly it had instructions for setting the priority on the factory valve - which BTW, looks like any other priority valve. At full flow, roughly one third of full flow to the PS and the remainder to the loader. Lower flows prioritize to the the PS.

It was common on all those early tractors with priority & PS to lose some power to the steering at low rpm or when using the loader. No biggie. You get used to it or can raise the RPM to compensate. Most would probably rather suffer some loss of function rather than run an engine at full rated rpm all the time.

If what you have is an add-on power steering cylinder spliced into the steering drag link I expect it could be set up similarly. That form uses less fluid, but tends to leak. Still, it sure beats manual steerimg an FEL.

rScotty

 

[aczlan]

That is the way that Yanmar did it with their hydrostatic power steering. Before the FEL They used an adjustable divider with a priority circuit. Universal priority valves with adjustable percentage flow plus a relief valve are reasonably priced at hydraulic outlets like surpluscenter.com

I think that's how pretty much every OEM does it, they consider steering to be more important than loader movement.

Aaron Z

 

[pmsmechanic]

I Another way to compensate for reduced flow would be to buy and install a hydraulic pump with a larger displacement. However, I have not been able to find one that will fit my tractor.

The pump in the Yanmar in my 4410 has a tandem pump. One side is for the power steering and the other is for everything else. Would that be an option?

 

[etpm]

The pump in the Yanmar in my 4410 has a tandem pump. One side is for the power steering and the other is for everything else. Would that be an option?

I don't know. I like the idea of a tandem pump. I will try to find out if the pump for the 4410 will fit a YM2310. Is the 4410 a YM tractor?
Thanks,
Eric

 

[etpm]

Definitely put the divider before the loader. Does the divider you bought have adjustable flow rate for the priority circuit?

No, my divider is not adjustable, darn it. If I had known better I would not have bought it. If I have to I will buy an adjustable one. I hope I don't need to because I made a nice mounting plate for the one I have and the adjustable ones are quite different.
Thanks,
Eric

 

[etpm]

The pump in the Yanmar in my 4410 has a tandem pump. One side is for the power steering and the other is for everything else. Would that be an option?

The only 4410 I could find was a Deere that has a Yanmar engine. But all the pumps I found for that engine are not tandem. And, since my tractor is 20 years older I wonder if it would fit anyway if I could find one. Let's hope I don't need one.
Eric