L39, Aux Hydraulics and a Hammer

[sgrol]

Considering the purchase of an L39 to power and mobilize a soil probe that I built. Probe is a vertically mounted hydraulic cylinder with a Stanley MB 156hydraulic hammer attached. Operational wise, I engage the hydraulics (My setup uses an open center design), get off of the tractor and operate the cylinder and hammer with a 2 spool valve. I push and/or hammer the probe into the ground to take soil samples. Question is, will the aux hydraulics work ok with the hammer (not worried about the cylinder) and tractor not be damaged with the operation? Specs on the hammer: hydraulc pressure - 1800-2100 psi, flow range - 4-10 gpm. I have a flow control block plumbed into my hydraulic circuit.

BTW - excellent site

 

[MXZXGADE]

After my fifth trip to NAPA to get hose's cut and ends made I finally got my rear valve kit installed. Talk about a generic kit! This is my first complant about Kubota. Kit was 775$ rip off. Do some research if you can find just the valve you can make the rest for probably half the cost. My mistake I thought the Kubota stuff would be good, it wasn't.

 

[sgrol]

Sgrol,

Setup sounds like it should work Ok, you haven't indicated what the hydraulic hammer is mounted onto, loader or 3PH??[/QUOTE

Vic, The whole attachment will mount to the front loader quick attach. I built it to mount up to a Bocat skid steer and plug into aux hydraulic connections. I bought the L39 on Sat. Spoke to the service manager and told him what I needed to do. They are going to make me two hoses with quick connects. I will unplug the backhoe lines and plug in the hoses they make. The other end of the hoses will hook up to my machine. I have a two spool open center valve. One side operates the cylinder up and down and the other energized the hammer both spring back to center when released. Vic, I noticed that there were three hoses plugged into the backhoe. I know one is pressure, one return. What is the other for. Thanks for all of your input and help. Sorry for the delayed response. I was expecting an email when this thread was added to but none came.

 

[sgrol]

After my fifth trip to NAPA to get hose's cut and ends made I finally got my rear valve kit installed. Talk about a generic kit! This is my first complant about Kubota. Kit was 775$ rip off. Do some research if you can find just the valve you can make the rest for probably half the cost. My mistake I thought the Kubota stuff would be good, it wasn't.

Just curious, what did come with the kit. I'm assuming it was for the backhoe end. What are you powering with it?

 

[sgrol]

The third line is the "power beyond" line. It carries over residual hydraulic pressure downline of the joystick control.

Usually you have to "couple" the hydraulic lines back together on a TLB unit so the 3 point hitch will operate with the hoe off.

You are the second person that has told me that but, there are two handles under the seat in the back that you pull out for 3 Pt use and push in for backhoe use. Is the "coupling" old technology or still needed? A little confused on this.

 

[sgrol]

Well I purchased the L39. Now will attempt to get hydraulic power to my attachment. Apparently there are two power circuits feeding the backhoe. One circuit for bucket,boom and dipperstick and one for left and right swing. Three hydraulic connections feed the backhoe - one power for hoe, one power for swing and a common return. Under the seat are two valve control levers that divert hydraulic fluid either to backhoe (quick connects) or three point hitch raise and lower control. I plan to disconnect three lines to hoe and connect my attachment to the hoe power line and the common return, leave the hoe power lever in hoe position and switch swing power to 3 point hitch position to prevent a deadhead condition for that circuit.

 

[sgrol]

New problem: Can hook up my attachmment and run it fine but need the outriggers operational also. I unplug the backhoe hydraulics to run my attachment which disables the outriggers. AAAAAAAAAAAAArg! I am getting into unkown territory here but it looks like I will need to hook up some kind of hydraulic directional valve. Any suggestions are most welcome. I can call anyone who has the knowledge to help. Just shoot me an email at: sgrsbc-insurance at yahoo dot com.

 

[sgrol]

Ok, going to close this one out. The solution was so simple. I unplugged the backhoe return to tank connection. Plugged in my attachment's 'in' hose to backhoe return to tank and my attachment's 'out or return' to the tractor return to tank fitting. Basically just looped in my attachment downstream of the backhoe. Now everything has power as needed.

 

[eserv]

I'm happy it is working for you but you still haven't got it quite right!
The problem with the circuit as you are using it is that you are forcing the combined flow from both pumps to travel through your attachment. The flow of the two pumps are, ( main pump 11.07 gpm) and (swing pump 6.18 gpm).
This combined flow is higher than the rated capacity of the valve on your hammer. this will cause your hoe to be slower than normal, create unnecessary heat and put backpressure on your backhoe valve causing a potential leak.
You should remove the hose from P1 on your backhoe valve, connect it via a hose to the "P" port on your hammer valve, then return the oil from the hammer valve back into P1 port on the BH valve. This will direct the 11.07 gpm flow through your hammer valve then back to the backhoe, getting everything more or less into spec again. this will create backpressure in your hammer valve, possibly making it's seals leak, but at least it isn't the Kubota that is leaking!
Ed

 

[sgrol]

I'm happy it is working for you but you still haven't got it quite right!
The problem with the circuit as you are using it is that you are forcing the combined flow from both pumps to travel through your attachment. The flow of the two pumps are, ( main pump 11.07 gpm) and (swing pump 6.18 gpm).
This combined flow is higher than the rated capacity of the valve on your hammer. this will cause your hoe to be slower than normal, create unnecessary heat and put backpressure on your backhoe valve causing a potential leak.
You should remove the hose from P1 on your backhoe valve, connect it via a hose to the "P" port on your hammer valve, then return the oil from the hammer valve back into P1 port on the BH valve. This will direct the 11.07 gpm flow through your hammer valve then back to the backhoe, getting everything more or less into spec again. this will create backpressure in your hammer valve, possibly making it's seals leak, but at least it isn't the Kubota that is leaking!
Ed

Not sure how you know what the rated flow of my valve is but let's bat this around. When I hook up this way I have to run the tractor at about 1500 rpm to get the hammer to work correctly. Any lower RPM makes the hammer fire too slowly. That sounds to me like I am not backing up the hydraulics, unless I'm missing something. I can see what you are saying and it makes sense, I'll give it a try and see how she goes. Thanks for the commentary. Hopefully I can get everything working happily together.

 

[eserv]

You wrote in your first post that the flow rate for the hammer is 4 -10 GPM.
Your hammer will work OK but you'll usually want to run your hoe at faster than 1500 rpm, that is when you will back up your hydraulic pressure.
Ed

 

[sgrol]

You wrote in your first post that the flow rate for the hammer is 4 -10 GPM.
Your hammer will work OK but you'll usually want to run your hoe at faster than 1500 rpm, that is when you will back up your hydraulic pressure.
Ed

Ah, sure did. I was thinking of the spool control valve which,I think, is rated at 20 gpm. So, what you are saying is, I am creating unbalanced hydraulics with my current hookup by forcing both pumps through one circuit? I certainly don't want to hurt the tractor.

 

[eserv]

I don't think having the flow combined is as much of a concern as forcing the 17 gpm through all that hose and fittings to your hammer and back. After all, Kubota already have it combined in the return line to tank. all of the oil has to make that trip anytime you are running the tractor. It will restrict the performance of your tractor some and generate more heat. the backpressure on your backhoe valve may cause it to leak from the spools also because it was never designed to operate with full pressure on the drain side. It might just be happy as a clam though! The problem with changing it like I suggested is that you probably will have to run the engine even faster to operate that hammer properly. Remember, rated flow on the pumps is at full throttle.
Ed

 

[sgrol]

I don't think having the flow combined is as much of a concern as forcing the 17 gpm through all that hose and fittings to your hammer and back. After all, Kubota already have it combined in the return line to tank. all of the oil has to make that trip anytime you are running the tractor. It will restrict the performance of your tractor some and generate more heat. the backpressure on your backhoe valve may cause it to leak from the spools also because it was never designed to operate with full pressure on the drain side. It might just be happy as a clam though! The problem with changing it like I suggested is that you probably will have to run the engine even faster to operate that hammer properly. Remember, rated flow on the pumps is at full throttle.
Ed

Thanks Ed. I didn't think about max rated flow being at full power, have to remember that. I'll hook it up like you suggested and see how she goes. It may take a while but I will report back here how it goes. Thanks again for your input.