Backhoe & Power Beyond Question

R_squared · Sep 17, 2008

The basic question is can the power beyond inlet on a tractors hydraulic manifold be used as a return? My tractor has a Prince LVR loader control valve with joystick and power beyond port. My tractor also has a hydraulic manifold block with a power beyond, a pressure outlet and a return inlet. Currently, the power beyond from the Prince LVR is connected to the power beyond on the tractors hydraulic manifold for 3-point lift control. I want to make a bulkhead near the rear remotes that have a pair of quick disconnects and a short jumper hose connecting them. One hose to the bulkhead will be from the Prince LVR power beyond. The hose from the Prince LVR to tractor hydraulic manifold will be discarded. The other hose from the bulkhead will be connected to the tractors hydraulic manifold power beyond. The short jumper hose will be connected to both of the bulkhead mounted quick disconnects when the backhoe is not being used, this completes the loop for 3-point lift control. When you want to use the backhoe you would have to remove the short jumper hose and connect the backhoe inlet and outlet hoses to the bulkhead. The backhoe inlet would connect to the power beyond from the Prince LVR and the backhoe outlet would connect to the tractors hydraulic manifold block power beyond. Is this loop safe to use or does the backhoe outlet have to be teed into the tractors hydraulic manifold block return inlet? The backhoe hose kit is a pain to use. If this loop is doable then you would not have to crawl under the tractor to disconnect the line from the hydraulic manifold block power beyond and connect it to the backhoe inlet and connect the backhoe outlet to the tractors hydraulic manifold block return inlet and visa versa when removing the backhoe. I contacted the manufactures of the related equipment and could not get an answer because each did not want to make comments on the operation of other manufactures equipment. Thanks!

JDeereman · Sep 17, 2008

R_squared said:
The basic question is can the power beyond inlet on a tractors hydraulic manifold be used as a return? My tractor has a Prince LVR loader control valve with joystick and power beyond port. My tractor also has a hydraulic manifold block with a power beyond, a pressure outlet and a return inlet. Currently, the power beyond from the Prince LVR is connected to the power beyond on the tractors hydraulic manifold for 3-point lift control. I want to make a bulkhead near the rear remotes that have a pair of quick disconnects and a short jumper hose connecting them. One hose to the bulkhead will be from the Prince LVR power beyond. The hose from the Prince LVR to tractor hydraulic manifold will be discarded. The other hose from the bulkhead will be connected to the tractors hydraulic manifold power beyond. The short jumper hose will be connected to both of the bulkhead mounted quick disconnects when the backhoe is not being used, this completes the loop for 3-point lift control. When you want to use the backhoe you would have to remove the short jumper hose and connect the backhoe inlet and outlet hoses to the bulkhead. The backhoe inlet would connect to the power beyond from the Prince LVR and the backhoe outlet would connect to the tractors hydraulic manifold block power beyond. Is this loop safe to use or does the backhoe outlet have to be teed into the tractors hydraulic manifold block return inlet? The backhoe hose kit is a pain to use. If this loop is doable then you would not have to crawl under the tractor to disconnect the line from the hydraulic manifold block power beyond and connect it to the backhoe inlet and connect the backhoe outlet to the tractors hydraulic manifold block return inlet and visa versa when removing the backhoe. I contacted the manufactures of the related equipment and could not get an answer because each did not want to make comments on the operation of other manufactures equipment. Thanks!

This can be made to work provided no valve downstream of the bh is ever to be used or touched (on purpose or by accident). most bh manufacturers consider this a dangerous setup and would tell you that the bh must exhaust directly to an unblocked (unblockable) return path. this achieves two things for them. no back pressure is ever seen by the bh circuit and no accidental operation of the 3-point is possible.

Theo

kennyd · Sep 17, 2008

I would do it the way JD does on the mid-framed CUT's...That is to add three QD's to the rear instead of two like you suggested. The third is just a hose for the return-to-tank line.
So you would have three connections at the rear:

>PB Out
>PB In (goes to the 3PH)
>RTT Return to tank for backhoe operation.

R_squared · Sep 17, 2008

Thanks guys for your suggestions. I could not find a good description of what exactly happens at the power beyond port on the tractor manifold. Does it have any pressure or flow when the hydraulic system is at idle? Does it have any pressure or flow when the loader valves are activated? Same questions for 3-point operation. I think Ken D, 3 QDs suggestions will work well. You would still use the short jumper hose when the backhoe is off to complete the power beyond loop for the 3-point operation. The good thing is that proper length hoses can be made and they would be permanently routed under the tractor. Also, there would be no QDs under the tractor where they would be more likely to cause contamination. Ill miss crawling on the ground though.

kennyd · Sep 17, 2008

The PB "loop" ALWAYS has fluid flowing through it. When all the valves are in neutral then it's the full flow of the pump, when a valve is activated, then whatever the fluid the valve does not redirect to the work port will continue to flow through the PB loop to the next valve in series.

The three ports at the rear is the best way IMHO. I can post a schematic and possibly pictures of the JD setup if needed.

JDeereman · Sep 17, 2008

R_squared said:
Does it have any pressure or flow when the hydraulic system is at idle? Does it have any pressure or flow when the loader valves are activated? Same questions for 3-point operation.

In an open center system with pb there will always be flow through the system at idle but only low residual pressure. once you operate a valve anywhere within the system, pressure builds in the system up to that valve (and through that valve for its particular use). downstream pb flow is effectively shut off (or partially shut off) until the valve is returned to the neutral position again. operating your fel control valve while the bh is in use will interfere with the bh momentarily but cause no harm. the same is not true if operating the 3-point levers in your originally proposed scheme because it would place a sudden back pressure on the bh circuit and potentially bind the 3-point arms to the bh frame or even worse pinch one or more delicate body parts. ouch!

Theo

R_squared · Sep 17, 2008

Ken G no need to post visual aides. The fun is in figuring out all the fittings needed and having the hoses made to your specifications.

Theo Thanks for the better PB pressure and flow explanations.

Guys, I did spend time searching through the archives on the power beyond subject, but the content was weak. Hopefully this thread will help future people understand what goes on with the power beyond.

mgrohman · Sep 23, 2008

Hi, thought I would post on this thread how I did this, for commentary and critique.
I needed to add a rear valve to raise and lower my mower-conditioner, which has a single acting cylinder. I think what I have done is appropriate. I basically had hoses made that Tee into the line that comes out of the 'PB' port on my loader control valve (pointing to it with my knife in the picture; the one I Teed into is to the right of the blade). This line already had a quick-disconnect connection at its midpoint, so I just had my hoses made with the opposite QD's. I purchased a Converta valve at TSC ($122) and converted it to single-acting by installing the supplied plugs (instructions for this are on the outside of the box. The instructions aren't very good, but I called them and got help right away). With this setup you use the work port labeled 'B', and 'A' is plugged.
Although itｴs not pretty (can't believe it rusted in one day!), this all works and works well and got me on the field cutting. The the only downside is the way I have it, the lever works opposite of what you're used to. However the above posts about 'PB return is not being a proper return port' have me worried (my system return is the hose marked with electrical tape in the picture). The lines do get fairly warm, but I'm fairly sure this is normal.

Also worth noting that the valve mfr made sure to mention this valve is not for raising and lowering something that can't drop a touch before it goes up (not an issue for my moco).

kennyd · Sep 23, 2008

mgrohman said:
Hi, thought I would post on this thread how I did this, for commentary and critique.
I needed to add a rear valve to raise and lower my mower-conditioner, which has a single acting cylinder. I think what I have done is appropriate. I basically had hoses made that Tee into the line that comes out of the 'PB' port on my loader control valve (pointing to it with my knife in the picture; the one I Teed into is to the right of the blade). This line already had a quick-disconnect connection at its midpoint, so I just had my hoses made with the opposite QD's. I purchased a Converta valve at TSC ($122) and converted it to single-acting by installing the supplied plugs (instructions for this are on the outside of the box. The instructions aren't very good, but I called them and got help right away). With this setup you use the work port labeled 'B', and 'A' is plugged.
Although itｴs not pretty (can't believe it rusted in one day!), this all works and works well and got me on the field cutting. The the only downside is the way I have it, the lever works opposite of what you're used to. However the above posts about 'PB return is not being a proper return port' have me worried (my system return is the hose marked with electrical tape in the picture). The lines do get fairly warm, but I'm fairly sure this is normal.

Also worth noting that the valve mfr made sure to mention this valve is not for raising and lowering something that can't drop a touch before it goes up (not an issue for my moco).

Welcome to TBN

I am glad your valve works for you-BUT-in general, you CANNOT "T" into pressure lines on open center hydraulic systems. All new valves must be plumbed in series to work properly. I would guess it's working for you because it is a SA cylinder and does not need a lot of pressure to raise the mower.

mgrohman · Sep 23, 2008

I actually was going to T into the 'In' line until I read your posts warning about that. I guess I thought I was doing the right thing by T'ing into the PB line - not so? So is the way I have it OK except I should have the return (i.e. the 'Out' from my new valve) go somewhere else? I have time to change this now because I'm not cutting hay again until next summer.
Marty

kennyd · Sep 24, 2008

mgrohman said:
I actually was going to T into the 'In' line until I read your posts warning about that. I guess I thought I was doing the right thing by T'ing into the PB line - not so? So is the way I have it OK except I should have the return (i.e. the 'Out' from my new valve) go somewhere else? I have time to change this now because I'm not cutting hay again until next summer.
Marty

Marty,
You should have a hose that runs from the PB port on your loader valve to the IN port on the new valve. The PB port on the new valve should go to wherever the original line went to (presumably the 3PH). Then the OUT of the new valve should go to the tank. You CAN Tee low pressure return lines, but NOT high pressure lines.

If the new valve in placed in "parallel" with the loader valve, then the fluid will take the path of least resistance back to the tank, and that won't be through your new valve. ALL valves MUST be in "series"

Clear as mud?

JDeereman · Sep 24, 2008

kennyd said:
Marty,
You should have a hose that runs from the PB port on your loader valve to the IN port on the new valve. The PB port on the new valve should go to wherever the original line went to (presumably the 3PH). Then the OUT of the new valve should go to the tank. You CAN Tee low pressure return lines, but NOT high pressure lines.

If the new valve in placed in "parallel" with the loader valve, then the fluid will take the path of least resistance back to the tank, and that won't be through your new valve. ALL valves MUST be in "series"

Clear as mud?

Kennyd - i don't think that valve has a pb port. just in and out ports. all he can do is feed it from fel pb and return flow to the next-in-line pb user (in series as you point out). not ideal and potentially dangerous per discussion above but otherwise he needs a valve with pb.

Theo

mgrohman · Sep 24, 2008

Thanks for the comments. Theo is right, the new valve doesn't have a PB port. It has an open center design, so to my (probably flawed) way of thinking, the FEL setup doesn't know it's there unless I actuate said new valve, which is fairly rare. Basically I only raise the Mower Conditioner if I am going to run over something, like maybe a finance manager.
This tractor, a Kubota L3710, does not have external cylinders for actuating the 3PH. I have the 'out' from the new valve going back to where the PB went before, which looks to me like it is a tank return. I will see if I can consult the appropriate page in the book and possibly scan and post it here. Essentially what you're telling me is, if I actuate this valve while I have something raised with the 3PH, I could cause myself a sichyation, correct?
Marty

JDeereman · Sep 24, 2008

mgrohman said:
Thanks for the comments. Theo is right, the new valve doesn't have a PB port. It has an open center design, so to my (probably flawed) way of thinking, the FEL setup doesn't know it's there unless I actuate said new valve, which is fairly rare. Basically I only raise the Mower Conditioner if I am going to run over something, like maybe a finance manager.
This tractor, a Kubota L3710, does not have external cylinders for actuating the 3PH. I have the 'out' from the new valve going back to where the PB went before, which looks to me like it is a tank return. I will see if I can consult the appropriate page in the book and possibly scan and post it here. Essentially what you're telling me is, if I actuate this valve while I have something raised with the 3PH, I could cause myself a sichyation, correct?
Marty

Marty - that old fel pb out line had to be going somewhere. i assume you have no backhoe. do you have a rear remote set? does your pb feed the 3-point? the 3-point doesn't need to have external cylinders to use pb. the physical connection to the 3-point may not be real obvious.

but if your pb line really wasn't there to feed anything and was just routed back to a tank return point for some possible future use, then you are fine once you change the fel pb out "tee" that you spoke about to a simple series connection as kennyd had pointed out.

Theo

kennyd · Sep 24, 2008

On most CUT's like JD's and the Kub's the 3PH is the last valve in the circuit. I will bet that PB line terminates to the tranny case, where internally it feeds the 3PH.

I will venture to say all you need to do is remove that T you have, and leave the OUT port go to where the PB line went to and you will be fine.

mgrohman · Sep 25, 2008

Kenny - I misspoke - I guess I meant that functionally I 'Teed' into the lines, but in actuality, I did have new hoses made that fit into the existing quick-disconnect junction in that PB line - basically I undid that quick-disconnect, and connected my new hoses. These are the in and out for my new valve. So I don't have any actual Tees in my system. This was based on some of your very good posts on the matter, that one should avoid Tees in hydraulics. In fact I bought some Tees before I read your posts and have to return them.
Marty

kennyd · Sep 25, 2008

mgrohman said:
Kenny - I misspoke - I guess I meant that functionally I 'Teed' into the lines, but in actuality, I did have new hoses made that fit into the existing quick-disconnect junction in that PB line - basically I undid that quick-disconnect, and connected my new hoses. These are the in and out for my new valve. So I don't have any actual Tees in my system. This was based on some of your very good posts on the matter, that one should avoid Tees in hydraulics. In fact I bought some Tees before I read your posts and have to return them.
Marty

So then, I apologize for busting your chops

Sounds like you are good-to-go then with the way you have it!

I was basing ALL of my comments on what you wrote in your first post:

I basically had hoses made that Tee into the line that comes out of the 'PB' port on my loader control valve (pointing to it with my knife in the picture; the one I Teed into is to the right of the blade).

mgrohman · Sep 28, 2008

That's OK - I deserve it! I wrote it wrong.
On another topic I've seen debated - I did use the white Permatex thread sealer on all of the pipe threads, like in and out of the new valve. I would say it's definitely needed, because I left it off of one fitting by accident, and it leaked.
Of course the sealer should be avoided on any compression-type fitting like the PB port on the loader valve.
Marty

Willl · Sep 28, 2008

kennyd said:
I would do it the way JD does on the mid-framed CUT's...That is to add three QD's to the rear instead of two like you suggested. The third is just a hose for the return-to-tank line.
So you would have three connections at the rear:

>PB Out
>PB In (goes to the 3PH)
>RTT Return to tank for backhoe operation.

Hi Kenny, this makes me question how the heck my 790 is plumbed for it only has 2 connections at the rear for my BH. (see attached)

I know my 3pt is still alive with the BH in circuit cause I can still hydraulically raise them for alignment during BH installation. But this doesn't make any sense beings the BH has only 1 return line. Does not 1 return line from the BH mean it MUST go directly to the tank ?

With a 2 connection setup like mine, what would happen if I forgot to rehook my return line after removing BH and started the tractor ? Instant system relief noise ?

If I wanted to add aux valve for TNT or whatever, what plumbing setup would be advisable ?

Studying my hyd schematic, seems the steering circuit just loops around and never sees the filter. I'm I seeing that correctly ?

kennyd · Sep 28, 2008

Hello Will

Hi Kenny, this makes me question how the heck my 790 is plumbed for it only has 2 connections at the rear for my BH. (see attached)

I know my 3pt is still alive with the BH in circuit cause I can still hydraulically raise them for alignment during BH installation. But this doesn't make any sense beings the BH has only 1 return line. Does not 1 return line from the BH mean it MUST go directly to the tank ?

The small CUT's like mine and the 2305, 2320, 2520 only have the one return for the PB circuit and that feeds the 3PH. There was a change in the mid-framed CUT's in the PB kit that added the extra QD that is a direct return-to-tank line (look in JDParts and you will see OLD and NEW under the PB for like a 4300 and 4400 series machines)
So in the tractors like ours with only one return, the 3PH stays active all the time.

With a 2 connection setup like mine, what would happen if I forgot to rehook my return line after removing BH and started the tractor ? Instant system relief noise ?

You got it! Instant relief for sure. If you left it running like that than overheating of the hydraulic fluid would occur and possible pump damage.

If I wanted to add aux valve for TNT or whatever, what plumbing setup would be advisable ?

Just put the new valve in-line, the PB port is not needed in this case. I have done it to my tractor as well as quite a few others who have 2520's. I can link some post's if you want?