My First Grapple - Hydraulics

[MarcusCarr]

This is the scariest part of this project because I don't know anything about hydraulics.

I had a situation where a quick connect came apart at the back of the tractor...where my backhoe connects. When this happened it deadheaded the fluid and I almost burned up my pump. I vaguely remember the person that helped me with the situation say something about closed systems will do that. You have to have a return for the fluid. Still...no idea what this system is.

I will attach some pictures to this thread that might help with my questions.

Questions...

Do I have an open or closed system?

Can I connect lines and a lever to my existing system?

What lever do I need? It doesn't have to be on the stick, I will just bolt it on somewhere.

Am I missing anything?

 

[MarcusCarr]

1

 

[MarcusCarr]

2

 

[MarcusCarr]

3

 

[MarcusCarr]

4

 

[MarcusCarr]

5

 

[MarcusCarr]

6

 

[MadReferee]

Please fill in your profile so we can see where you are located and what kind of equipment you have. It will be alot easier to get answers that way.

</font><font color="blue" class="small">( Do I have an open or closed system?)</font>

Just about every tractor under 100 hp is an open center system whereby the pump is continously pumping. Yours is no different.

</font><font color="blue" class="small">( Can I connect lines and a lever to my existing system?)</font>

If you mean can you add an aux control valve, or a diverter, the answer is yes.

</font><font color="blue" class="small">( What lever do I need? It doesn't have to be on the stick, I will just bolt it on somewhere. )</font>

You need to purchase a stand alone open center directional control valve with at least one spool. The spool characteristics will depend on what you are going to use the valve for. You can mount it anywhere you want.

</font><font color="blue" class="small">( Am I missing anything?)</font>

Yes. If this is for a grapple then you can make things much easier by using a diverter with a button on the joystick to switch one of the loader functions to the grapple. Do a search here on TBN for Grapple and you will find several recent discussions on how to do this.

You still have plenty of homework to do. Everything you need to know has been answered here in the past, some of it within the last few weeks. Start searching, and fill in your profile.

 

[MarcusCarr]

I did some research and I believe I have figured out how to do the hydraulic part of this task.

I am going to add a bracket to the back of the tractor, above the bracket in picture 6 (post 7 of this thread) This will have two quick connects that can be attached to the quick connects in the picture that are usually either attached to the backhoe or looped back on eachother (as they currently are in the picture.

From those quick connects, I will have oil delivery and oil return which will be connected to a single spool, 4-way, 3 position, spring center, open center valve. After I plug my oil delivery and return lines into this spool, I will be left with two ports on the spool. One to deliver oil to the cylinder and another to return oil from the cylinder.

Another question that come to mind...

When I connect these lines, they will have air in them. Do I have to bleed the lines or will the air be pushed out by using the system?

Thank you for your help.
Marcus

 

[MadReferee]

</font><font color="blue" class="small">( When I connect these lines, they will have air in them. Do I have to bleed the lines or will the air be pushed out by using the system? )</font>

They will be self bleeding. All you have to do is cycle the cylinder a few times.

One concern is with your hydraulic connection scheme on that Mitsubishi. Normally, on most tractors, when the backhoe is connected the 3pt is disabled. Not knowing how your hydraulic circuit is, you may have problems. You might want to post in the Mistubishi forum and ask about the hydraulic circuit on your model.

 

[MarcusCarr]

My 3 point can still be raised and lowered while the backhoe is being used. However, I need to be careful as raising the 3pt while the backhoe is attached will move the the entire backhoe unit up and down (I think). When I bought the tractor, he told me not to pull back on the level while the backhoe was attached, because it would raise the 3pt against the backhoe.

Here is the valve that I think I should be using for this project...

Valve

 

[MadReferee]

That valve is a little big for your tractor. But it is cheap although Surplus Center has the same valve (#9-6765) for 15% less.

If you are looking for a smaller footprint/weight valve you should check out Surplus Center. They have several that would be a better choice, but a few bucks more, depending on your tractor's implement gpm flow.

 

[MarcusCarr]

Thank you for the advice.

I checked Surplus Center and found this...

Valve

This one has 1/2" connections all the way around. The GPM for my tractor is nowhere near 20. I think it is around 8 GPM.

 

[MadReferee]

Your total gpm may be around 8 but that probably includes the power steering. Your actual is more than likely 5-6 gpm.

That valve is the same as the one from Northern only cheaper.

If your implement flow is over 5 gpm then I would go with a single spool Prince SV, open center with double acting spring return to center spool (9SV-1-X-B). It's slightly smaller than the single spool valve you found and will be easier to install and it is expandable if you decide to at a later date. Down side is it's a few bucks more.

 

[MarcusCarr]

Mad,

Can you add a link to the valve that you just recommended?

Thanks,
Marcus

 

[MadReferee]

Right here. Just choose work section B.

Surplus Center Prince SV

 

[MarcusCarr]

Looks handy to have the ability to expand the valve system. I noticed that this one has SAE 8 and the other has 1/2" NPT. What is the difference between the two?

 

[MadReferee]

1/2" NPT fittings are physically way larger than SAE 8. SAE 8 is a more appropriate fitting size for smaller valves where you will be connecting 3/8" or 1/4" hoses.

1/2" NPT has tapered threads with the outer thread diameter at .84" and the inner diameter at .53".

SAE 8 is straight 3/4"-16 with an OD of .75" and and ID of .66". The SAE fittings for the valve will use an O-ring for sealing. SAE 8 to 3/8" adapters are commonly used here.

 

[MarcusCarr]

Are you able to tell from the attached photo what fittings I am currently using? I this project, I will need to purchase a male and female quick connect that will match up to the quick connects shown in the photo. The black lines you see here all have "1/2" printed on them.

Thanks,
Marcus

 

[MarcusCarr]

moved to the My first Grapple thread