Aux. hydraulics on BH

   / Aux. hydraulics on BH #1  

afish

Silver Member
Joined
Mar 27, 2008
Messages
132
Location
Michigan
Tractor
Kubota L-39
This is part of another post in kubota forums (l39 lots of questions) but it has transitioned to more of hydraulics discussion so I thought I might get more response here. Anyway I would like to add hydraulics to the backhoe on a L39 for a thumb and possibly a hyd. PHD in the future. I'm not really looking to get the parts from Kubota do to price. From the posts in the other thread sounds like its pretty much the same as 3rd. function on a loader. I dont care if it is operated by foot or toggle on the BH joystick. someone already said I need a open center valve. Anyway here are my question's

1. I figured I need a valve like the one WR long sells which seems to be a hyvair valve but on the WR long website it says its not sized to run Hyd. motor When I looked at the Hyvair web site it looks like the valve WR long sells is either a D03 valve is rated at 24 gpm or the D05 is 40 gpm seems like that would handle the L39 flow of 11 gpm not positive on that since the WR long site dosnt get very specific on what valve they are selling. Am I missing something why couldnt these valves handle a motor?

2. I also checked surplus center offerings and found the eaton-victor valve here=

Surplus Center Item Detail

Thing is they have two with open centers one with work ports closed in neutral (says for operating D/A cylinders) and one with work ports open in neutral (says for operating Hyd. motor) since I want to do both does this mean if I buy the one with closed ports in neutral I would have to hold down the toggle switch to spin the PHD (Not a big deal to me since I would not be holding it down all day only intermittently) or is there a bigger problem I dont see?

3. The other problem with this valve is its only rated for 10.5 gpm does this mean it would have a problem with the 11 gpm from the L39 or does it mean 11 gpm into the valve and 10.5 gpm out of the valve. I know its only .5 gpm just want to make sure I'm not going to blow anything up.

4.Can someone explian the difference between open/closed centers. Do I need an open center so the hyd. fluid can flow through the valve and back to the tank?
 
   / Aux. hydraulics on BH #4  
1. I figured I need a valve like the one WR long sells which seems to be a hyvair valve but on the WR long website it says its not sized to run Hyd. motor When I looked at the Hyvair web site it looks like the valve WR long sells is either a D03 valve is rated at 24 gpm or the D05 is 40 gpm seems like that would handle the L39 flow of 11 gpm not positive on that since the WR long site dosnt get very specific on what valve they are selling. Am I missing something why couldnt these valves handle a motor?
The valves close the work ports when they are closed, so if the motor is spinning fast it is still trying to pump fliud while it coast's to stop. Since a PHD turns so slow...you will not have problem.
2. I also checked surplus center offerings and found the eaton-victor valve here=

Surplus Center Item Detail

Thing is they have two with open centers one with work ports closed in neutral (says for operating D/A cylinders) and one with work ports open in neutral (says for operating Hyd. motor) since I want to do both does this mean if I buy the one with closed ports in neutral I would have to hold down the toggle switch to spin the PHD (Not a big deal to me since I would not be holding it down all day only intermittently) or is there a bigger problem I dont see?
I would use the "work ports closed in neutral" for the reason I already stated.
3. The other problem with this valve is its only rated for 10.5 gpm does this mean it would have a problem with the 11 gpm from the L39 or does it mean 11 gpm into the valve and 10.5 gpm out of the valve. I know its only .5 gpm just want to make sure I'm not going to blow anything up.
This rating is the amount of fluid the can pass through the valve without causing a restriction. I would use one rated at or higher that you machine.
4.Can someone explian the difference between open/closed centers. Do I need an open center so the hyd. fluid can flow through the valve and back to the tank?
You definitly need a OC (open center) valve. You pump is called a "fixed displacement" pump, meaning it is ALWAYS pumping fluid-if you interrupt that flow for to long bad things can happen!
 
   / Aux. hydraulics on BH #5  
Oops, my bad. Was thinking smaller tractor.

Actually the L39 specs out at 23 gpm, so I definitely went the wrong direction.

Edit; Heck, I can't even get that right. Missed the **

"**11 GPM for loader/backhoe, 6.2 GPM for backhoe boom swing, 6.2 GPM for power steering."
 
   / Aux. hydraulics on BH #6  
Oops, my bad. Was thinking smaller tractor.

Actually the L39 specs out at 23 gpm, so I definitely went the wrong direction.

No biggie:D

Plus, the one you linked (which I put on my FEL 4 years ago and cost $150:eek:) is a diverter valve, not a 3rd function that can be used independently of the other controls.
 
   / Aux. hydraulics on BH #7  
Is that 11 GPM at 2600 or so engine RPM ?
Do you run the hoe at 2600 RPM ?
I don't and I wouldn't run a PHD at that sort of engine speed either.
 
   / Aux. hydraulics on BH
  • Thread Starter
#8  
I'm not sure what the rpm's are at 11gpm. I actually haven't got the l-39 yet waiting for it to be delivered:( thats probably why I have time to ask so many questions:) ). I have so many projects I want to build I dont see how I will get much seat time for awhile. But no I dont usually run it at high rpms when I have used a backhoe Good point. but at the same time I wouldnt want to restrict my flow alot just in case But going from 11 to 10.5 is no big deal in my book. So as long as I am understanding correctly I'm on the right track for a valve and either of the two Hyvair or eaton will work as long as they are open center and work ports closed in N so it will just come down to price I guess.
 
   / Aux. hydraulics on BH #9  
I'm not sure what the rpm's are at 11gpm. I actually haven't got the l-39 yet waiting for it to be delivered:( thats probably why I have time to ask so many questions:) ). I have so many projects I want to build I dont see how I will get much seat time for awhile. But no I dont usually run it at high rpms when I have used a backhoe Good point. but at the same time I wouldnt want to restrict my flow alot just in case But going from 11 to 10.5 is no big deal in my book. So as long as I am understanding correctly I'm on the right track for a valve and either of the two Hyvair or eaton will work as long as they are open center and work ports closed in N so it will just come down to price I guess.

Where did you get the 11GPM figure? I just looked up the specs for the L39 and found 23.4 GPM listed in the specs:confused:

BUT:
You need to rate the valve at the full flow the tractor can produce at ANY RPM since the new valve will be in series whenever the backhoe is installed.
 
 
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