Go Bottom3PT Hydraulics Problem - Kubota B2150
 | ChrisG
Join Date: Jul 2003 Posts: 6 Arlington, Indiana 
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2002-06-11 39465
Recently purchased a used B2150HST with 4wd and power steering. The previous owner added a self-centering hydraulic control valve from the hydraulic block to the fender. The hydraulics work, but not quite as I would expect.
To lower the 3PT, I move the position control lever to the down position (makes sense so far).
To raise the 3PT, I first have to move the position control level to the up position, then use the hydraulic contol valve on the fender to lift the 3PT (2 steps - awkward).
The 3PT works as long as I leave the directional valve turned counterclockwise. If I turn it clockwise, as the Operator's Manual indicates for when the hydraulic outlet is in use, the relief valve opens and the 3PT no longer operates.
Since its a lifting problem, I don't think it has to do with the lowering speed control. The pump works since both the 3PT and the power steering work.
I'm mechanically inclined, but this is my first tractor and I haven't worked on hydraulics before. I've read through previous messages on the Board looking for any similar postings. Found a response from TomG indicating a stuck or open poppet value as a reason for not lifting. Could this be the (or one of the)problems, and how do I get to it?
Any suggestions are appreciated before its off to the dealer.
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 | Peters
Join Date: Feb 2002 Posts: 3034 Northern AL 
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2002-06-11 39470
My old MF operates similarly. I can lower or raise the 3 Pt with the valve opened. I can also raise and lower with the valve. ....
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| ChrisG
Join Date: Jul 2003 Posts: 6 Arlington, Indiana
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2002-06-11 39471
If mine worked like the old MF, it wouldn't be so bad.
I can only lower the 3PT using the position control level.
I can only raise the 3PT by moving the position control lever to up then using the valve on the fender. ....
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 | Murf
Join Date: Dec 1999 Posts: 7249 Toronto Area, Ontario, Canada
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2002-06-11 39472
Chris, hydraulics, like electricity, is something that requires a firm grasp on the theory since unlike a mechanical operation, there is nothing to look at or study, it happens 'behind the scenes'. Having said that I think the cost of OEM Kubota parts is the second part of your problem. It is not unheard of for a 'power beyond plate' to cost $700, considering it is nothing more than a pound of simply-machine cast iron, it is outrageous, it is nothing more than a hydraulic 'splitter', allowing the fluid to go to multiple valves simultaneously without losing pressure to the others. Having said that, it is very common to see people put remote hydraulics in series with the 3pth, instead of in a parallel circuit as you would have with a 'power beyond plate'. Basically what is happening is that the remote valve has been installed right smack in the middle of your 3pth hydraulic circuit, when you move the valve it allows the 3pth to operate (or not depending on the motion). Unfortunately you need the equivalent of this 'splitter' my suggestion would be to find a good machine shop and have one made, either that or remove the valve, etc., and the system will return to normal. Best of luck. ....
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| ChrisG
Join Date: Jul 2003 Posts: 6 Arlington, Indiana
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2002-06-11 39474
Murf, thanks for the response and advise. I don't need the remote valve for the implements I'm using.
You're definitely right about understanding hydraulics. It's a black box that I really don't feel a burning need to understand, just so it works.
I am still a little confused about the 'power beyond plate'. I'm sure it's my lack of hydraulics understanding, but I would have thought that since the remote valve was run from the hydraulic block's auxilary ports that it would have automatically 'split' the pressure. Bad assumption I guess. Of the 3 auxilary ports on the block(to pressure, to neutral, to tank), the remote value was hooked up to the 'to pressure' and 'to tank' ports.
Thanks again. Hopefully all will be fixed once I pull the remote valve. ....
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| Murf
Join Date: Dec 1999 Posts: 7249 Toronto Area, Ontario, Canada
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2002-06-11 39480
Chris, things make a little more sense now. A traditional remote valve for that type of use should have 3 lines, not just two. I think most people here would agree that a remote valve is an incredibly handy gadget, even if all you do is get a hydraulic top-link for the 3pth. The fix could just be as simple as putting the proper valve on your machine, the valve should be connected in such a way as to have pressure in one side and out the other and back to the pressure feed for the machine ('neutral' in your case I believe) and then the return to the 'tank' port. Since yours is lacking one line the valve must be moved to accomplish the same thing. Best of luck. ....
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| ChrisG
Join Date: Jul 2003 Posts: 6 Arlington, Indiana
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2002-06-11 39482
Murf, thanks again for your reply. My lack of hydraulic understanding is really showing now.
I assume that having a remote value with 3 lines would allow an implement like a hydraulic top link to move both in or out depending on which way the lever was moved.
Since my valve is only using 2 lines I can only have flow in one direction. As long as the valve wasn't being operated (no flow), wouldn't that be the same as removing the valve and hydraulic lines from the hydraulic block auxiliary ports? If so, then the 3PTH won't lift when moving the position control lever to the up position.
Is it possible that the remote valve, connected the way I described was a 'work around' of a different valve or blockage problem in the 3PTH lift hydraulics? ....
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| TomG
Join Date: Feb 2002 Posts: 5406 Upper Ottawa Valley
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2002-06-12 39493
Chris: It sounds like you've got an 'odd-ball' valve installed in the high-pressure line to the 3ph. I'm guessing that there's an inlet line that comes from a hydraulic block and a return line that goes to the TX case. A control valve outlet on the valve probably runs back to the 3ph high-pressure line. If the valve on the fender is for a two-way cylinder, then one direction would operate the 3ph and the other would operate an external device. That would be a very unusual hookup.
If I've guessed correctly, then operating the valve on the fender is the only way to get oil to the 3ph.. When the valve is centred, oil goes to the sump through the valve's return line, but the 3ph would lower normally through it's own return to the sump.
I'll guess some more that there is a hydraulic manifold block that has a diverter valve and pressure and return ports for an auxiliary system. If there were nothing connected to the auxiliary system ports, changing the diverter valve to 'auxiliary' blind-ends the system and the pressure relief valve would open.
If all this guessing is right, a solution is simply to remove the valve on the fender--a new line might be required. At least on my Ford 1710, there is a steel hydraulic line that runs from the block directly to the remote (3ph) valve. That way the 3ph would operate normally and an auxiliary device like a loader could be plumbed into the auxiliary system ports. Plumbed in this manner, both the loader and the 3ph will operate normally (but one at a time) without the need to switch a diverter valve.
The main thing to understand about open centred hydraulic systems is that oil circulates all the time and there always must be a return path to the sump. Operating a valve blocks the line and opens a path to a cylinder. Pressure is developed so the piston moves and more oil can flow. If it's a double acting cylinder (power in both directions) then there is oil on both sides of the piston. Pressure moves the piston in one direction, and oil on the other side of the piston flows out to a return line. However, the pump always pumps, and if no return line is present, then the relief valve opens, which is a return line in its own right.
....
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| TomG
Join Date: Feb 2002 Posts: 5406 Upper Ottawa Valley
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2002-06-12 39499
I just had an additional thought about the valve on the fender. If it works as I suspect and if it's a log splitter type, then it may have a detent position. With the control level in the detent position, the 3ph may work normally. Valves that have detents can be identified by pushing the control lever fully in one direction. A slight additional push 'clicks' the lever in place and the valve will remain in an open position. I run my backhoe similarly but use a bungee cord to hold a control valve on my loader valve open. However, the return oil from the backhoe valve returns through a cylinder line to the loader valve assembly.
If a cylinder line from the ‘fender’ valve feds the 3ph then the 3ph control valve would route oil to the sump or to the lift cylinder depending on the quadrant lever position. There would be no return oil flow through the valve assembly on the fender.
In all this speculation, it would be helpful to know if the valve assembly on the fender is a power beyond type. A power beyond valve has one high-pressure inlet port and two return ports in addition to its cylinder line ports.
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| Murf
Join Date: Dec 1999 Posts: 7249 Toronto Area, Ontario, Canada
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2002-06-12 39502
Chris, I suspect the basic problem is the valve itself. It sounds, from your description, that somebody has installed a 'closed center' type valve instead of an 'open center' valve. As the names imply, your valve (closed center) does not allow any fluid to pass the valve until it is moved 'off center' (the resting position of the valve). In an open center setup the fluid comes in one side and right back out the other in the resting position. In this case it would continue merrily along to your 3pth without any intewrvention on your part. As I stated before, at least a phone call, if not a visit, to a good hydraulic shop can probably get the problem solved to your satisfaction for relatively little money. Best of luck. ....
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| TomG
Join Date: Feb 2002 Posts: 5406 Upper Ottawa Valley
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2002-06-13 39519
Murf: I thought about a closed centre valve as well. I re-read the original post, and I think the 'self-centering valve' and the 'directional valve' are two different things. I think the self-centering one may be a typical spooling valve and the directional one a diverter valve on a hydraulic block. The relief valve seems to open only when the directional valve is rotated, which is what would happen with a diverter valve when noting is connected to the auxiliary system ports. If the spooling valve is in the high pressure line and it had a closed centre plug, then the relief valve would open whenever the valve was centered. However, all this is a little hard to figure from the description.
I just keep wondering if this is some unusual plumbing where the 3ph is fed from a cylinder line of a spooling valve. The only reason for doing such a thing I can think of is that pushing the valve one way would power the 3ph, but pulling it the other way could power an external device (backhoe for example). Return oil from an external device could be gotten back to the sump in various ways.
Such an arrangement may seem odd, but it might seem a bit more convenient to some people than having hoses connected to the auxiliary ports of a manifold block and having to change a diverter valve frequently.
....
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| ChrisG
Join Date: Jul 2003 Posts: 6 Arlington, Indiana
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2002-06-13 39521
WOW, lot's of feedback and advice! Thanks Murf and TomG!
Let me try to summarize the situation again, responding to your previous responses as I can best describe them. Thanks for the education and your help.
- What I've previously described as the 'remote valve' is the valve on the fender that is run from the auxiliary ports on the tractor's hydraulic manifold block.
- What I've previously described as the 'directional valve' is what I think TomG refers to as the diverter valve. The valve is located-on/part-of the tractor's hydraulic manifold block.
- 3PH lowers using the position control lever
- 3PH raises by first placing the 3PH position control lever in the 'up' position and then moving the remote valve (diverter valve on the hydraulic manifold block in normal position)
- The remote valve is connected to the hydraulic manifold auxilary ports using 2 hoses. It is connected to the 'to pressure' and 'to tank' ports as identified in the B2150's Operators Manual. The 'to neutral' auxilary port is not used.
- I don't know (lack of understanding) if the remote valve is a power beyond type. The valve appears to have 3 ports, 2 hooked up as described above, and one that appears to be capped. The 2 ports that are hooked up are labeled but I don't recall what they say or which runs to which auxiliary port on the hydraulic manifold block (I'm at work and the tractor is at home, so I can't check till later). There is a screwed on cover in the line of the valve action and 2 couplings for hooking up an auxiliary implement. I don't recall seeing a brand or model anywhere.
- The tractor has concrete/cement spatters around the 3PH, rear PTO and ROPS. The tractor may have been used with a 3PH concrete mixer, but I don't know that for sure. I don't know how a 3PH concrete mixer works, but could it be that the 3PH was just a support and the remote value used only to dump the concrete, with the PTO turning the drum?
- The remote valve is self-centering (can be moved forward or back from the center position and springs back to center once you let go). I don't believe that the valve has a detent position at TomG described (again, I'm at work). I assume that I would have noticed any aditional movement and 'click'.
- The 3PH will raise by moving the remote value to either the forward or back position (it raises both ways), but the 3PH position control lever MUST be in the up position, first.
- When the diverter valve is turned to auxiliary, the relief valve operates and the 3PH will not lift.
I hope I was clearer in my descriptions and terminology. Thanks for any additional feedback. ....
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| Murf
Join Date: Dec 1999 Posts: 7249 Toronto Area, Ontario, Canada
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2002-06-13 39531
Chris, with the limited information I have gleaned from your decription, I would guess (and it's strictly that without taking pressure readings, etc.) that if you connected the two capped-off ports that everything would work as it should normally. I still suggest that, if it is at all possible, have a hydraulics shop look at the machine. If nothing else the information you will pick up will be worth the price of admission (if there is any charge at all). Best of luck. ....
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| TomG
Join Date: Feb 2002 Posts: 5406 Upper Ottawa Valley
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2002-06-14 39542
The 3ph should work normally with the diverter in ‘remote’. That may be a separate problem for the rest of the hydraulics. I'd start by making sure the plumbing on the spooling control valve assembly (on the fender) is right. If it's a power-beyond type and has one control valve there should be five ports and the assembly should have three sections bolted together.
The control valve is in the centre and has two connections for the cylinder lines, which may be capped if no auxiliary device is connected. The inlet section has one connection and the outlet section has two connections. Most hydraulic valves are stamped with codes that identify the ports. The inlet port is identified with 'IN' or 'P' for pressure. That line runs directly to the pressure port on the manifold block.
A power-beyond outlet section has two ports. One port is labeled 'PB' for power beyond. That line runs directly to the return port on the manifold block. The other port on the outlet section often is labeled 'T' for tank but may be unlabelled. That line ordinarily runs to a fitting on the side of the TX/DIFF cases.
The connection for a spooling valve without power-beyond is identical except there is no tank line. Using a valve without PB in series with another downstream valve such as the 3ph works but runs the risk of damaging the valve if both valves are operated at the same time.
The PB line carries the pump flow when no control valve is operated. If the PB port is capped, the system will work basically as described. With the diverter in 'aux' and the control valve is centered there is no return path to the sump and the relief valve will open. However, the valve would operate anything connected to the cylinder lines. As Murf noted, some spooling control valves may be used with either open or closed centre systems. They are supplied with a plug for closed centre system use that must be removed if installed on an open centred system.
The tank line carries cylinder exhaust oil. If there are no double acting cylinders connected to the control valve, then the tank line should never carry oil. If the tank and PB lines were reversed, anything connected to the control valve should work normally, but when the valve is centred flow would go to the sump rather than to the manifold block and the 3ph wouldn't work. There are possible permutations to this problem, but this post has gotten too long.
....
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