Adding selective control valve to John Deere 750

[Moondoggy]

I recently acquired the power angle blade made for my John Deere 750. I need to add the selective control valve and was hoping to get some advice. I found the original 2 handle control valve new for $1180.00, plus shipping of course. I would really prefer a single joystick type control. The valve must have a float position. The 750 is Open center hydraulics, constant flow, 2030 psi. It looks by the service manual it must have power beyond. Any recommendations for what may be a good fit for this tractor and any other random advice would be appreciated.

 

[jd4310man]

I had a very similar problem with my 655. I built a front blade and needed to add a hydraulic valve to control it. My tractor didnt come with the dual selective control valve so I added an aftermarket one that has power beyond capability. The tractor comes standard with a flow divider to power the steering and rockshaft functions. I removed the factory metal line from the pump and had a new hose made to feed the new valve first and then another line to power up the factory flow divider from the power beyond port thus powering up the whole system. Here is a valve that would work 2 SPOOL COMPACT 1 GPM JOYSTICK CONTROL VALVE | Directional Control Valves | Hydraulic Valves | Hydraulics | www.surpluscenter.com Hope this helps

 

[Moondoggy]

I had a very similar problem with my 655. I built a front blade and needed to add a hydraulic valve to control it. My tractor didnt come with the dual selective control valve so I added an aftermarket one that has power beyond capability. The tractor comes standard with a flow divider to power the steering and rockshaft functions. I removed the factory metal line from the pump and had a new hose made to feed the new valve first and then another line to power up the factory flow divider from the power beyond port thus powering up the whole system. Here is a valve that would work 2 SPOOL COMPACT 1 GPM JOYSTICK CONTROL VALVE | Directional Control Valves | Hydraulic Valves | Hydraulics | www.surpluscenter.com Hope this helps

Thanks jd4310man. That looks like a good fit. Saved me some time searching.

 

[jd4310man]

Here is a few pics of the valve and hoses on the 655

 

[oldnslo]

Normally steering gets priority in a circuit for safety reasons.
Where is the relief valve in this circuit?

 

[CalG]

As of yet, I have not been able to justify the "steering first| safety angle.
I'm trying to imagine being in a situation when Steering is the important function, and the operator is unwilling (or unable) to let go of the bucket or boom control handle. In fact, when things get screwy, I want the bucket DOWN first, then I can deal with the angle of the front wheels.

Perhaps you can offer a situation that I have not considered. But I've got no issues with hard turning while lifting or scooping.


Doesn't the tractor internal system contain an over pressure relief that covers the entire system including any PB extension? I made a post asking the same not long ago. Seems that any PB relief valve is redundant. But???? Are there exceptions?

 

[jd4310man]

Usually each valve has a relief valve that can be set to a specific pressure for the job at hand.

 

[CalG]

Usually each valve has a relief valve that can be set to a specific pressure for the job at hand.

But only the lowest pressure setting is available to the system. All higher settings become invalid. So if the loader valve relief is set to 2ksi, that is all the 3pt will ever see. And lift capacity will follow.

 

[oldnslo]

As of yet, I have not been able to justify the "steering first| safety angle.
I'm trying to imagine being in a situation when Steering is the important function, and the operator is unwilling (or unable) to let go of the bucket or boom control handle. In fact, when things get screwy, I want the bucket DOWN first, then I can deal with the angle of the front wheels.

Perhaps you can offer a situation that I have not considered. But I've got no issues with hard turning while lifting or scooping.

Some possible concerns depending on the valve style:

Regenerative tilt circuit: No flow is going to the power beyond circuit while using regenerative dump. common SCUT's

lift or lower at full speed: no flow to the power beyond circuit.

Blade tilt: again full speed no flow to the steering circuit.

I know on my previous Kubota BX and now on my Branson I perform all of these operations while driving and not having steering would be a problem for me.

Connecting into the line between the flow divider and the current directional control valve provides steering and functions. Granted the auxiliary functions will operate slower since part of the flow is going to steering.

 

[kthompson]

What type of steering systems do these tractors use? Is the hyd a power steering system supporting a full linkage system or a hyd steering system
with no linkage, no hyd pressure no steering ability?

 

[Moondoggy]

Here is a few pics of the valve and hoses on the 655

Nice job.

 

[LD1]

Have you chosen a valve yet?

I am a bit confused as to what you are asking.

You want remotes to run power angle on a blade. Then you mention it MUST have float and that you would prefer joystick?

Joystick means a 2 spool valve, which is 2 sets of remotes. Float isnt going to do any good on a rear angle blade. And you only need 1 remote. But nothing wrong with wanting more. Float is a nice option for a top link or side link cylinder if you have future plans.

Typically when looking at a joystick valve, most are designed for loaders and float is quite common to get. But regen is also quite common to get. For remotes, you dont need or want regen. Because some valves are regen ONLY.

You also need to get one with an optional PB plug. Not sure how your deere is configured, but usually on a loader tractor, the PB off the loader valve feeds the 3PH. You need to insert the valve between these two. So the PB off the loader goes to feed the remote (SCV), then the PB off of that feeds the 3PH.

Dont forget you need a separate tank line for the SCV also. That can be tee'd into the loaders return.

Too many people get PB and return (tank) mixed up.

 

[oldnslo]

What type of steering systems do these tractors use? Is the hyd a power steering system supporting a full linkage system or a hyd steering system
with no linkage, no hyd pressure no steering ability?

Not 100% sure but believe that if you lose hydraulic power steering becomes very difficult but still possible similar to power steering on a car.

 

[Moondoggy]

Have you chosen a valve yet?

I am a bit confused as to what you are asking.

You want remotes to run power angle on a blade. Then you mention it MUST have float and that you would prefer joystick?

Joystick means a 2 spool valve, which is 2 sets of remotes. Float isnt going to do any good on a rear angle blade. And you only need 1 remote. But nothing wrong with wanting more. Float is a nice option for a top link or side link cylinder if you have future plans.

Typically when looking at a joystick valve, most are designed for loaders and float is quite common to get. But regen is also quite common to get. For remotes, you dont need or want regen. Because some valves are regen ONLY.

You also need to get one with an optional PB plug. Not sure how your deere is configured, but usually on a loader tractor, the PB off the loader valve feeds the 3PH. You need to insert the valve between these two. So the PB off the loader goes to feed the remote (SCV), then the PB off of that feeds the 3PH.

Dont forget you need a separate tank line for the SCV also. That can be tee'd into the loaders return.

Too many people get PB and return (tank) mixed up.

It's the model #375 FRONT utility blade made by JD specifically for this tractor. As i I don't have a loader on it I wanted to add a more modern Joystick Valve. JD4310man sent me a link for a nice valve. I have the service manual that shows how to plumb it with PB. I have a rear snowblower but with a gear tractor it is inefficient for lighter snows. I would never want to plow in reverse with a gear tractor.

 

[LD1]

That makes alot more sense.

That valve that surplus center carries I believe is a "Brand" brand valve. And they are pretty good for the price.

But you can get them with several options, float being one of them.

Another option is Regen on second spool. Dont need that for a front blade, but if you ever have plans on putting a loader on the tractor, its something to consider.

And you will forsure need the optional PB plug.

Good luck

 

[Moondoggy]

I received my Cross joystick loader valve from Surplus center. It is nothing like the stock JD SCV so I have to make a bracket to fit. If anyone has added an aftermarket valve to a 650 or 750 I would be interested in how you mounted it. I also have to plumb it. The controls ports are all SAE 8. I have the service manual that shows where all the hoses connect to the tractor, and it says a plug must be installed in the auxiliary outlet port of the rockshaft piston cover. Does anyone have the part # of this plug? Also, if anyone has a 650 or 750 tractor without power steering I would be interested in how the hydraulic lines are run and what type of fittings and size of hoses are used. I did get the plow and cutting edge sanded and painted while waiting for the control valve. Next pic I'll keep my big, fat finger out of the way!