Kubota L5740, adding a mini loader valve to control rear implements

[cstamm81]

Unique hydraulic question for the group. On my L5740, I have added a 4 spool electric solenoid valve body plumbed into the backhoe hydraulic loop, and I also have 2 factory remotes. I am looking to add a compact loader valve with float function, it will be a great way to control 2 separate functions on a ditch bank flail mower I have and a rotating tree grapple I hope to own. Both of these implements work much better with one of the 2 needed spools having a float function. The loader valve would be mounted near the remote valve levers: https://www.surpluscenter.com/.../6-GPM-2-Spool-Metro...
Now, my question: I was thinking of using one of the factory remotes to feed the loader valve, I would only crack the remote valve to provide a small amount of flow through the loader valve when needed, holding the remote valve open with some type of invention. Holding the remote valve open will provide a small amount of continuous flow through the 6gpm loader valve. Is this going to heat up my hydraulic oil, or should it be fine for intermittent use?
My other options are: add a third factory float valve / remote, pricy option and I would prefer to control these implements with a loader valve. Or, I could add a higher gpm loader valve to the existing power beyond port on the electric valve bank, the issues here are returning the loader valve outlet to tank and having to deal with a much larger loader valve.
Thanks in advance.

 

[oldnslo]

If attempting to meter flow with directional valve the metered flow rate will change depending on the load. Yes anything you do to restrict or meter flow will create heat.

 

[LD1]

I hope the installation of the solenoid valves isnt done cause I only see two hoses going to it and no PB sleeve.

You CANNOT use the backhoe loop alone to feed that bank. You need to add a 3rd line back to tank.....and the two BH loop lines are your inlet and PB

 

[cstamm81]

I hope the installation of the solenoid valves isnt done cause I only see two hoses going to it and no PB sleeve.

You CANNOT use the backhoe loop alone to feed that bank. You need to add a 3rd line back to tank.....and the two BH loop lines are your inlet and PB

That pic is of my current setup, and I have been using it this way. The solenoid valve bank in the picture is the last valve in that circuit, and the tank port goes directly to tank. I’m not feeding any other valves currently, which is why I’m not using the PB outlet.
All I did was use the existing backhoe loop to feed the inlet and tank outlet for this solenoid valve bank, did I do something incorrectly?

 

[LD1]

Show a pic of where your "tank" outlet is connected at the other end. My guess is it continues on to feed the 3PH. Therefore any weight of anything carried on the 3PH is now backpressure on the tank port of the new valve.

The "backhoe" loop can get around needing a PB and a third hose because you CANNOT have anything on the 3PH at the same time as the backhoe. And when the backhoe is removed, the hoses are looped and no valve in the system.

Also why if you read the kubota manual.....it will tell you to leave the 3PH control lever in the down position and not to move it when the backhoe is on

 

[cstamm81]

Show a pic of where your "tank" outlet is connected at the other end. My guess is it continues on to feed the 3PH. Therefore any weight of anything carried on the 3PH is now backpressure on the tank port of the new valve.

The "backhoe" loop can get around needing a PB and a third hose because you CANNOT have anything on the 3PH at the same time as the backhoe. And when the backhoe is removed, the hoses are looped and no valve in the system.

Also why if you read the kubota manual.....it will tell you to leave the 3PH control lever in the down position and not to move it when the backhoe is on

Hard to see, but it's the line feeding the silver long sweep silver 90 degree elbow, which has a large banjo fitting on the end of it. I'm trying to verify by looking at hydraulic circuit diagrams, can't be certain, but I think you may be correct in that this is feeding the 3PH.

 

[LD1]

If it is indeed feeding the 3PH then you really need a PB plug in the valve to feed that, and add a tank hose.

 

[cstamm81]

If it is indeed feeding the 3PH then you really need a PB plug in the valve to feed that, and add a tank hose.

I really appreciate you pointing this out to me. I assumed it was returning to tank, not feeding the 3ph and factory rear remotes. I have been using it this way for about a year, using the remotes and 3ph all the time. Surprisingly no issues with the valve block or the outlet on the valve block.
I ordered the PB plug, I'll move the existing outlet line to the PB port. Now to the tricky part from what I can see, where can I return the outlet on the solenoid valve bank to tank? Hard to see under there, but I'll need a large enough port to return to tank.

 

[ericm979]

Often there is a tank line from the loader valve. You could tee it into that at either end. You may need to get under the tractor or take some body work off, especially if you want to get at the transmission end of that line.

 

[cstamm81]

Often there is a tank line from the loader valve. You could tee it into that at either end. You may need to get under the tractor or take some body work off, especially if you want to get at the transmission end of that line.

Looking like all of the loader valve lines are hard piped, so teeing into one of those will be cute. I’ve been reading, seems others have had issues trying to find a place to return to tank on the 40 series grands. The only successful story I can find is a guy running a laser grader blade, he made a fitting and returned to tank through the factory hydraulic fill port.

Am I correct in saying that fluid will only return to tank through the valve outlet when I actuate a cylinder using this valve bank? Otherwise, flow will continuous through the PB port on the valve. Returning fluid to the fill port will create oil aeration, due to it literally dumping into the tank. But, I’m hoping as there will only be small amount of flow when a cylinder is actuated, that I could get away with returning in this manner with no ill effects.