Tapping into tractor hydraulics

[jd4310man]

I have an 87 John Deere 655 C.U.T. I just completed a hydraulic snow plow build for it and am installing the hydraulic lines and fittings to make it work. It did not come from the factory with the dual selective control valve that was used to run the front attachments like a snow plow or loader. I need to tap into the system some how to power an external control valve that I added to control the blade. I found a port on top of the divider valve that splits the flow to the steering valve and the rock-shaft valve. But the blade only works when I activate the rock shaft valve and the new blade valve. It is an open center system. Can I interrupt the metal line coming off the pump and add a second flow divider to split the flow two ways? Is it possible to add another pump to power the blade ? Thanks for any help.

 

[CADplans]

Hydraulic oil is no different than a garden hose,,, if you use a "T" connection, the oil will flow the path of least resistance.
You need a series connection to the new valve,, and a power beyond connection.

 

[Tx Jim]

Ditto what CADplans stated hyd connection must be attached in series on open center hyd's such as a JD 655. I think you could insert a scv valve in between the connections of the hose in your 2nd photo if that hose leads to loader valve.

 

[buickanddeere]

Factory parts book and just bolt on the valves

 

[jd4310man]

I think I will divert the metal line that goes from the pump to the factory priority flow divider( first pic), and run it to the new control valve and use the power beyond port on the valve to supply flow back to the factory priority flow divider. Not sure how it will affect the steering though.

 

[Tx Jim]

I think I will divert the metal line that goes from the pump to the factory priority flow divider( first pic), and run it to the new control valve and use the power beyond port on the valve to supply flow back to the factory priority flow divider. Not sure how it will affect the steering though.

If you tap into(not tee into) line from pump to priority valve every hyd function activated will stop/slow oil flow to power steering

 

[bigdeano]

You need to put your new valve in series with the line that goes to the rock shaft valve. The power beyond port on your new valve would then go to the rock shaft valve. If you don't have the power beyond fitting for your valve you'll have to get one.

Your power steering will work normally.

That's how I see it anyway.

 

[LD1]

Yep, cant just go Tee'ing and Tapping everywhere there is a port.

It looks like the loader valve is possibly an aftermarket valve? Looks like pressure is coming in on the back side nearest the dash, and the tank-return is coming off the outside.

Since I see no other lines, I assume this valve is last in the series? Hard to tell without knowing where those two lines come from / go to.

But you should be able to buy a PB cartridge for that loader valve. You need to remove the tank return line, install the PB cartridge. Coming out of the PB port/cartridge on the loader valve, is the high pressure you need for the valve you are adding. That loader valve will still need its own return line.....and its okay to tee that line for the return port of the new valve.

Another option, since you have a loader, would be to install a diverter on one of the loader circuits.

 

[bigdeano]

I don't see any loader. The valve in the pictures is the new one he's adding I think.

 

[jd4310man]

Yes, im adding a new aftermarket valve to operate the blade I just built. It has a power beyond port on the outer side, next to the return to tank port. Here is a link to the prince valve. http://www.princehyd.com/portals/0/wolverine/ValveData.pdf
The port closest to the tractor is the incoming pressure line from the pump. I dont see why having the new valve plumbed directly from the pump and then powering the rest of the system with the power beyond will hurt anything? I cannot separate the rock shaft valve from the rest of the system as its hard plumbed into the system from the flow divider. There is no external hose feeding it. I wish it was like that as it would be the better route to take. Got to love how Deere engineered this thing! Unless it was the Japs that did it?