Adding another set of rear hydraulic lines.

[JimR]

I have a 1995 Cub Cadet 7275. My tractor currently has a set of rear hydraulic lines for attachments like a woodsplitter etc. There is no valve with these lines except for the switchover lever from the 3 Pt hitch. Whatever piston type attachments you use would require a dedicated valve to operate the attachment that you want to run unless it is a hydraulic motor of some sort. You can use either the 3Pt Hitch or the rear hydrauilcs, but not both at the same time. I recently bought a used Harley Rake that has a hydraulic piston for lowering and lifting the tines. How can I go about adding in another set of permanant LIVE hydraulics in the rear. I know that I will need to have a valve back there to operate the piston and allow a return route for the hydraulic fluid. At the same time I may as well add in another valve to operate a soon to be installed piston for one side of the 3 PT hitch setup to be used for titling attachments on the 3Pt hitch. I realize that the new valves need to be tractor mounted for this to work properly. I was thinking of tying it in on the return bypass line from the loader control valve. Could I also tie it in on the return side of the 3 Pt hitch hydraulics? The lines back there are small compared the the loader lines. Your thoughts and experience on doing this would be greatly appreciated. TIA, Jim R.

 

[Farmerford]

Jim:

We need to know more. How is the loader valve plumbed? Does it have two lines coming from the tractor hydraulic system or three? Can you use both the loader and three point hitch without having to switch a valve? I don't mean at the same instant, but one after the other without having to switch a valve like you have to for the three point hitch and rear outlets. Can you use the loader if the rear outlets are turned "on" with the selector valve you mentioned?

 

[JimR]

Jim:

We need to know more. How is the loader valve plumbed? Does it have two lines coming from the tractor hydraulic system or three? Can you use both the loader and three point hitch without having to switch a valve? I don't mean at the same instant, but one after the other without having to switch a valve like you have to for the three point hitch and rear outlets. Can you use the loader if the rear outlets are turned "on" with the selector valve you mentioned?

I have three lines going to the loader valve. Two go into the bottom end of it and the other goes into the top of the valve. I was just looking at my owners manual. It says to hook up the lines on hydraulic implements so that the impliment lowers when the lever is puched forward and raises when the lever is pushed backwards. I believe that the loader will not go up if the rear remote lever is in the active position. I do not have any attachments on the tractor right now to try it out. Nor can I get at my woodsplitter to try it.

 

[3RRL]

Jim,
I'm not sure about your loader valve and whether or not it has a power beyond port on it. If it does, you can plumb the new valve from that power beyond port. In other words, the new valve is plumbed after or behind your loader valve. If it does not, or you are not sure about it, your best bet MIGHT be to buy a 2 spool open center valve with power beyond in it and plumb it like this:

- First, find a good spot to mount your new valve so it gives you good access and control while viewing to the rear or sideways.
- Disconnect the line from the hydraulic pump going to the loader valve.
- Connect that line to your new valve where the port is to have power "in".
- On the new valve, use the "power beyond" port with the correct sleeve in it and run a line from that port back to your loader valve, where you have taken off the pump line. Now the loader valve is plumbed back up.
- On your new valve, find the "return to sump" or "exit" port.
- Run a line from that port to where the return line is to your hydraulic box. that is, where your loader valve return line to sump or reservoir is.
- You will need to install a "T" there to connect the new valve line to it.
- Now the new valve is plumbed and it is feeding your loader valve via it's power beyond port and
- It is returning to the hydraulic box or sump.
- Now hook up lines on the new valve ports that go to the new quick disconnects for your rear remotes.
- You will need a bulk head mount for the QD's mounted to the tractor.
- Then you can plug in your hydraulic lines to operate your implements, using the levers on your new valve.

You can search Surplus center as they have many valves and hydraulic cylinders to choose from.
When selecting a new valve and reading about them,
- Be sure the flow (gpm) is close to what your tractor pump produces.
- And that it is rated for (or more) your system pressure.
- Check the physical size of the valve.
- Look to see it is "open center".
- And that it has a "power beyond" port, already with the power beyond sleeve in it.
- If not, they should have one that fits the valve and get it.
- You can measure the hose length by using a garden hose as a measuring guide.
- Route it just like you would your hydraulic hoses.
- Make sure they are out of the way and have enough room to move/flex if required.
- Be sure to note the port threads and whether they are NPT, JIC or SAE/ORB.
- Then get your hoses made up to the correct length and with the correct end fittings on them.
- Probably Ø3/8 hose will do.
- Match all the fittings to the valve and cylinder ports.
- Learn about the different fittings available, NPT, SAE/ORB or JIC.

Another tip would be about the fittings... so this is my personal preference. I find that JIC are the easiest to work with and leak proof. Second or equal would be SAE or ORB fittings. Last is NPT because you really have to tighten them up and use a thread sealer. However, they are the most common and certainly work if the connection is good and tight. Discount Hydraulics has a great selection on hoses and will make them up for you. They also have a chart that tells you type and what thread and size the fittings are. Here is a link to it.

Discount Hydraulic Hose.com

Disclaimer:
I am no hydraulic expert by any means, but I have done this a couple times now with help I received here on TBN, especially from the late MadReferee who was a tremendous help to me. There may be other ways to do it, but I know this way works. All my plumbing came out great.
I hope this information will be of help to you.

 

[JimR]

Jim,
I'm not sure about your loader valve and whether or not it has a power beyond port on it. If it does, you can plumb the new valve from that power beyond port. In other words, the new valve is plumbed after or behind your loader valve. If it does not, or you are not sure about it, your best bet MIGHT be to buy a 2 spool open center valve with power beyond in it and plumb it like this:

- First, find a good spot to mount your new valve so it gives you good access and control while viewing to the rear or sideways.
- Disconnect the line from the hydraulic pump going to the loader valve.
- Connect that line to your new valve where the port is to have power "in".
- On the new valve, use the "power beyond" port with the correct sleeve in it and run a line from that port back to your loader valve, where you have taken off the pump line. Now the loader valve is plumbed back up.
- On your new valve, find the "return to sump" or "exit" port.
- Run a line from that port to where the return line is to your hydraulic box. that is, where your loader valve return line to sump or reservoir is.
- You will need to install a "T" there to connect the new valve line to it.
- Now the new valve is plumbed and it is feeding your loader valve via it's power beyond port and
- It is returning to the hydraulic box or sump.
- Now hook up lines on the new valve ports that go to the new quick disconnects for your rear remotes.
- You will need a bulk head mount for the QD's mounted to the tractor.
- Then you can plug in your hydraulic lines to operate your implements, using the levers on your new valve.

You can search Surplus center as they have many valves and hydraulic cylinders to choose from.
When selecting a new valve and reading about them,
- Be sure the flow (gpm) is close to what your tractor pump produces.
- And that it is rated for (or more) your system pressure.
- Check the physical size of the valve.
- Look to see it is "open center".
- And that it has a "power beyond" port, already with the power beyond sleeve in it.
- If not, they should have one that fits the valve and get it.
- You can measure the hose length by using a garden hose as a measuring guide.
- Route it just like you would your hydraulic hoses.
- Make sure they are out of the way and have enough room to move/flex if required.
- Be sure to note the port threads and whether they are NPT, JIC or SAE/ORB.
- Then get your hoses made up to the correct length and with the correct end fittings on them.
- Probably Ø3/8 hose will do.
- Match all the fittings to the valve and cylinder ports.
- Learn about the different fittings available, NPT, SAE/ORB or JIC.

Another tip would be about the fittings... so this is my personal preference. I find that JIC are the easiest to work with and leak proof. Second or equal would be SAE or ORB fittings. Last is NPT because you really have to tighten them up and use a thread sealer. However, they are the most common and certainly work if the connection is good and tight. Discount Hydraulics has a great selection on hoses and will make them up for you. They also have a chart that tells you type and what thread and size the fittings are. Here is a link to it.

Discount Hydraulic Hose.com

Disclaimer:
I am no hydraulic expert by any means, but I have done this a couple times now with help I received here on TBN, especially from the late MadReferee who was a tremendous help to me. There may be other ways to do it, but I know this way works. All my plumbing came out great.
I hope this information will be of help to you.

That sounds like the right route to take. One question I have is this. If you use an open center set of control valves, why do you need a return line? Wouldn't the oil just flow out of the rear valves to the loader control through the other feeder line that you installed to it?

 

[3RRL]

That sounds like the right route to take. One question I have is this. If you use an open center set of control valves, why do you need a return line? Wouldn't the oil just flow out of the rear valves to the loader control through the other feeder line that you installed to it?

Yes it would and many valves are set up that way if there is no power beyond port on it.
However, I was told it is better to use the power beyond port (from the new valve) to supply the loader valve and the new valve has it's own return to sump line to let any excess fluid go back to sump. But I've been told it can work like you say. Mad always recommended using a power beyond port to supply the next valve in line to avoid any problems and that was the best way to do it. Not knowing exactly why it is better that way, I always followed his instructions.

With that said, I do have a valve that controls my grapples. It does not have a power beyond port on it so the exit from it goes to the next valve in line, exactly how you describe. LOL ... Go figure?

Here are some links that may help describe the difference.
Hydraulic Sales & Services by Precision Fluid Power, Inc.
Hydraulic valve power beyond or high pressure carry over

I think this one has the best explanation about why you need to use power beyond and the advantages obtained by using a power beyond outlet and why it needs a return to sump.
http://www.baumhydraulics.com/UserFiles/File/terms_hydraulic%E2%80%A6ntrol_valve.pdf
And this last one which has a bunch of hydraulic reference stuff, one of which is the second link I posted.
Hydraulic Tutorials

These links will help with the explanations and guide you through your valve addition. BTW, I didn't know diddly squat before I learned on TBN. I followed instructions and ended up learning a lot about hydraulics. I was petrified scared at first but after I got into it, it was pretty common sense easy.

 

[JimR]

Yes it would and many valves are set up that way if there is no power beyond port on it.
However, I was told it is better to use the power beyond port (from the new valve) to supply the loader valve and the new valve has it's own return to sump line to let any excess fluid go back to sump. But I've been told it can work like you say. Mad always recommended using a power beyond port to supply the next valve in line to avoid any problems and that was the best way to do it. Not knowing exactly why it is better that way, I always followed his instructions.

With that said, I do have a valve that controls my grapples. It does not have a power beyond port on it so the exit from it goes to the next valve in line, exactly how you describe. LOL ... Go figure?

Here are some links that may help describe the difference.
Hydraulic Sales & Services by Precision Fluid Power, Inc.
Hydraulic valve power beyond or high pressure carry over

I think this one has the best explanation about why you need to use power beyond and the advantages obtained by using a power beyond outlet and why it needs a return to sump.
http://www.baumhydraulics.com/UserFiles/File/terms_hydraulic%E2%80%A6ntrol_valve.pdf
And this last one which has a bunch of hydraulic reference stuff, one of which is the second link I posted.
Hydraulic Tutorials

These links will help with the explanations and guide you through your valve addition. BTW, I didn't know diddly squat before I learned on TBN. I followed instructions and ended up learning a lot about hydraulics. I was petrified scared at first but after I got into it, it was pretty common sense easy.

Thanks for all the links. I will go through them and see what I can learn.

 

[JimR]

I used my Harley Rake today using the rear remotes. It worked just fine with the lever on the tractor. Of course I will still need the added valves to be able to use a side lift piston for tilting. That will be the next modification.