Adding 3rd control to Kubota L3710

jshwhite · Nov 14, 2011

I have a Kubota L3710 with a BushHog 2045 mid-mount front end loader. I'm planning on building a tree shear but first need to add a 3rd control for an auxiliary hydraulic hookup on the FEL. Sorry, I don't have much experience with hydraulics so I'm pretty much clueless!

The tractor has no auxiliary hookup, even in the rear, so all I'm working with is the FEL valve and associated lines. From the looks of it, there is a pressure, a return, and a power beyond line. I'm guessing at somehow putting a solenoid in the pb line?? I want to have full control of the loader while still putting full pressure into the tree shear.

I'm sure there is someone out there that has done it. Would anyone mind sharing a step-by-step of how they did it and what parts they used?

Speaking of parts, I really want to do it as cheap as possible. Any money saving suggestions are welcome!

One other question I had was whether there was any way to somehow plumb another valve in the system and forget the solenoid idea. Any thoughts on that?

Thanks!
Josh

nybirdman · Nov 14, 2011

Check W.R. Long for a valve kit:can't recommend Kubota's third function kit.

J_J · Nov 14, 2011

jshwhite; said:
I have a Kubota L3710 with a BushHog 2045 mid-mount front end loader. I'm planning on building a tree shear but first need to add a 3rd control for an auxiliary hydraulic hookup on the FEL. Sorry, I don't have much experience with hydraulics so I'm pretty much clueless!

The tractor has no auxiliary hookup, even in the rear, so all I'm working with is the FEL valve and associated lines. From the looks of it, there is a pressure, a return, and a power beyond line. I'm guessing at somehow putting a solenoid in the pb line?? I want to have full control of the loader while still putting full pressure into the tree shear.

I'm sure there is someone out there that has done it. Would anyone mind sharing a step-by-step of how they did it and what parts they used?

Speaking of parts, I really want to do it as cheap as possible. Any money saving suggestions are welcome!

One other question I had was whether there was any way to somehow plumb another valve in the system and forget the solenoid idea. Any thoughts on that?

Thanks!
Josh

Since you have PB, you are off to a good start. How much GPM's does the tree shear to operate with a good speed?

You could use solenoid valves, or a two spool valve with PB and install the valve in series with the loader valve, and run the output of the new valve to the 3pt.

The solenoid will not give you feather, and will cut at full force.

Here is a 10 GPM solenoid valve and you will need a sub plate off the the right of the page.

http://www.surpluscenter.com/item.asp?item=9-6136&catname=hydraulic

http://www.surpluscenter.com/item.asp?catname=hydraulic&item=9-5883-1

J_J · Nov 14, 2011

If you wanted the remotes on the rear for other things, then you would connect the series connection like this.

From pump, to FEL valve, a FEL PB out pressure hose to the IN port on the new valve at the rear, and the PB out of the new valve would connect to the 3pt. all of the OUT ports on all valves should go to tank.

If you have the hyd block, the connection is still in series going through the hyd block.

You could put as many spools as you want at the rear for more money.

Expect about $300 to $400

Does your tractor have the GPM's for the tree shear?

I did find your tractor has 7.8 GPM availiable.

You can not work both functions at the same time, as the FEL with levers fully engaged will take all the fluid to operate the cyl.

You would not normally use both at the same time, because when cutting, you don't move the FEL.

You could also use a diverter valve at the front and use the curl circuits to operate the shear. Then it is a matter of flipping a switch to go with curl or shear.

If you want hyd at the rear, then I would go with the 2,3,or 4 spool valve at the rear for things like T-N-T, hyd auger, etc.

jshwhite · Nov 15, 2011

Thanks for the info. I'm didn't realize how expensive it would be, so I might have to wait a bit before digging in, but I'll definitely be doing it asap!

I don't mind it cutting with full force as I'm thinking that I will need all the force the tractor has. I haven't built the shear yet so I don't know how many GPM's it will need, but I'm just hoping I'll have enough to run it

I'd love hyd at the rear, but right now just wanting to do it cheap. What about using a diverter? I hadn't thought of that. That sounds like a cheaper option maybe? Is that something available on surplus center? It's not finding it when I search for it.

Thanks again.

J_J · Nov 15, 2011

As far as power and pump size, if the pump can develop about 2500 psi, as soon as the engine is running, you have pressure and can use the hyd.

The cyl used will determine the force in lbs/tons. The pressure determines the force, and the GPM determine the speed.

The cyl pushing straight on has the most force, but if you push the blade at an angle, the force will be reduced.

If your tractor hyd does not provide enough GPM's, you could install a PTO pump.

Here are a few pictures of tree shears to give you some ideas.

I built the small red tree snipper to reach up in trees.