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X739 extra SCVs

7756 Views 15 Replies 5 Participants Last post by  X748SE
So I just bought a used X739. I can already see times where I want the 3PH to be on separate hydraulic circuits from the front. For instance, when I get a snow plow for next winter with hydraulic up/down and left/right, I'm out of SCVs, but I'd also like to have a rear blade for back dragging at the same time. Obviously, I want the rear blade and front blade on separate circuits. Similarly, if funds allow, eventually, I would like to have the CTC loader on this tractor. Again, the rear blade, as ballast and dirt leveler, should be usable on the back of the tractor at the same time. So I did some research and saw on mytractorforum where someone had added 3 extra SCVs to their X748.
2012 X748 "H5" Project - - The Friendliest Tractor Forum and Best Place for Tractor Information
I also ran across this thread where someone added a third SCV to an X485.
X485 H-3 conversion - - The Friendliest Tractor Forum and Best Place for Tractor Information
I am not nearly as skilled as the author of that first thread is. Frankly, messing with the linkage for the existing SCV scares me. However, I am mechanically inclined enough to do significant modifications, I just don't think I would be able to get those linkages perfectly lined up.

So that brings me to my idea. Right now, I'm thinking of adding a joystick valve with float on one spool such as this:
I am not sure where I would put the valve and the tractor is in storage for right now. I will figure that out later. Ultimately, this would be perfect to plug the loader into leaving the original two SCV spools free for the rear and/or a grapple, dump cart, etc. I am not as concerned about separating the deck lift from the other functions as others seem to be. I envision taking the autoconnect deck off when working with major front implements.

So I had two thoughts on connecting it up. My first and simpler option is to simply take the return line from the existing SCV and connect it to the pressure port on the new valve. Then the return line from the new valve needs to either go directly to the reservoir, or more likely, get connected to the other end of the original return line.

The second option, which I'm not even sure how feasible it is without looking at the tractors SCV is to get the power beyond port for the new valve, run the pressure line going to the existing SCV to the new valve instead, then the power beyond circuit from the new valve into the pressure port on the old valve. then tee the two return lines together and send them down the original return line to the tank. That is a lot of extra fiddling which may or may not be all that easy to do under there.

So does anyone have any thoughts on the benefits of either routing? Or, knowledge about how hard or easy it is to do what I want to do? Or, and alternatives I hadn't thought of?

Thanks for the feedback in advance.

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Lots of views, but no thoughts at all?

Do I need to offer :drinks:?
No luck!

I moved this tread to Lawn and Garden Tractors. Maybe it'll get better exposure here rather than Hydraulics.
No luck. I'm back to having to offer some :bigbeer:

Sorry I've been away!

I'm the one who originally added an additional 3 port SCV to my X748 for an H5 setup. The hydraulics on your machine is pretty much identical to mine.

If you are somewhat mechanically inclined then you should not be scared to make up those linkages. I used a coat hanger(s) as a template for the bend and routing of those linkages. When I made mine it really only took an afternoon to get the rods bent and aligned. To me this was easier then routing the hydraulic hoses!

From reading of what you want to do with your tractor and equipment, if I where you, this is what I would do.

1) Add a cable controlled joystick to control your existing John Deere 2 port SCV for front mounted implements: loader, blade, blower etc. Using a joystick over the column mounted levers is night and day different for front mounted implements. It is just more natural to use. Secondly only the cupholder would be modified/lost.

2) Add a new 2 Port SCV underneath your tractor and make linkages from your column mounted levers back to them. It really isn't as hard as you may think to make up those linkages. I can guide you through the process.

3) Use one of the new SCV ports to control your MMM and 3PH.

4) Use the other new SCV port and TEE it. Have one set of couplers at the rear (for dump trailer) and the other set of couplers somewhere up front so that a grapple (or whatever) could be attached to it. I would doubt it that you would use the rear and front ports at the same time.

Take a look a the enclosed PDF document that I wrote on adding a single port SCV to an X700 series tractor. It is written for my series of tractor but all the hydraulic info should be the same. It shows how to "tap" into the existing hydraulics to add the additional SCV and the basic parts that are needed.

From the threads that you have stated above and the enclosed PDF it should be give you a very good idea of the parts and the process required to add some additional hydraulic circuits to your tractor.


Roger, thanks so much for commenting and the *.pdf. I read through it once. That is clearly not enough times to fully understand it. I will need to read it again and again.

I think the first step to where I want to go is the joystick with cable operated control of the existing SCV. Can you share any details of that portion of the install? What part number or brand of joystick with cable control did you use, or will work with the existing SCV? Who made the JD X7XX SCVs, was it Prince? I have seen a cable joystick for Prince SV or RD5000 valves, but obviously, have no idea what brand / model JD used.

Thanks again!

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Thanks for the tips. I am torn now. If I first proceed with the joystick, that is great, but doesn't really add any NEW functionality.

On the other hand, since I have an X739 (post 2013 redesign) with the autoconnect deck, there is no way to know if what fit on your tractor will fit on mine. Although, I have a sneaking suspicion they are eerily similar under there.

Upon reading it again, that additional 3SCV looks crowded in there with the lines and levers. I am not sure I have the patience to make that work. If I tried to add a new 2SCV, that might be easier to route everything. But you know how I would be kicking myself down the road if I wanted to upgrade to a 3SCV, all that money for the 2SCV would be lost.

Would it be possible to install a 3SCV, but, only use 2 of the valves? I imagine I would have to make a loop between the outlets of the unused SCV or something? However, the SCV that I wouldn't hook up is the 4x4 lever one, which is probably the easiest to do. Ugh! decisions, decisions.

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