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Rannsachair
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I was thinking the same and hone the bores.
chrismac
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I have spent one or two hours on the T-cut for sure
Untitled by chrismac2012, on Flickr
Untitled by chrismac2012, on Flickr
DSC02874 by chrismac2012, on Flickr
chrismac
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managed to get one quote back, £260 plus vat each, thats pushing the not financially viable button to be honest.
chrismac
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The power beyond feeds back into the tractor system to operate the 3 point linkage, I have drawings from when I was sussing it all out.
I am unsure if its open or closed centre, (I dont understand what that means, does it mean in closed centre a raised loader would sit and if open it would drop)
Open centre means that when the spools are all in the neutral position, oil flows back to the tank (in practice, this means the Pressure is connected to Return/Tank)
Closed centre means that when the spools are all in the neutral position, the pressure line is blocked/capped, and remains at full system pressure.
Closed centre results in quicker response, but is more expensive to implement, as you either need to add a pressure dump valve, or on demand supply.
Whereas open centre is far more common, as it's cheaper to implement, as you only need a basic fixed displacement pump.
Pressure carryover simply extends the pressure line, which in the case of open systems means the connection to Return has to be at the last spool valve block, but for a closed system, you could simply split and run the pressure line to multiple spool blocks.
Closed centre means that when the spools are all in the neutral position, the pressure line is blocked/capped, and remains at full system pressure.
Closed centre results in quicker response, but is more expensive to implement, as you either need to add a pressure dump valve, or on demand supply.
Whereas open centre is far more common, as it's cheaper to implement, as you only need a basic fixed displacement pump.
Pressure carryover simply extends the pressure line, which in the case of open systems means the connection to Return has to be at the last spool valve block, but for a closed system, you could simply split and run the pressure line to multiple spool blocks.
Munkul
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thinking about it, it will have to be an open centre spool setup, because that tractor isn't sophisticated enough to have a pressure compensated pump. It'll be a gear pump most likely - like nearly all sub 100hp tractors.
BUT, since it's a power beyond system, it will have closed ports and a HPCO. You still have a T line on each spool block, but the P line extends all the way through to the end, and the last block in the system returns P to T.
EDIT: m_c explained it perfectly lol
Sorry I didn't understand before - now I do, it's the HPCO, I hadn't heard of it called the "power beyond" port before but googling it, it seems to be a common term. Was getting confused and hadn't read the whole thread.
Anyway, in response to the actual problem, it's still unclear as to which spool type you have so it's hard to say. Almost like its a J port valve (A & B to T at centre) and not a E port (A and B closed at centre).
You use a J port spool with load holding valves on the rams, but it won't work at all without load holding, which loader rams usually don't have, so it needs to be an E port spool of some description.
BUT, since it's a power beyond system, it will have closed ports and a HPCO. You still have a T line on each spool block, but the P line extends all the way through to the end, and the last block in the system returns P to T.
EDIT: m_c explained it perfectly lol
Sorry I didn't understand before - now I do, it's the HPCO, I hadn't heard of it called the "power beyond" port before but googling it, it seems to be a common term. Was getting confused and hadn't read the whole thread.
Anyway, in response to the actual problem, it's still unclear as to which spool type you have so it's hard to say. Almost like its a J port valve (A & B to T at centre) and not a E port (A and B closed at centre).
You use a J port spool with load holding valves on the rams, but it won't work at all without load holding, which loader rams usually don't have, so it needs to be an E port spool of some description.
chrismac
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Thanks for all the replies, its given me lots to think about,
I think possibly I know the reason my spool valves aren't doing what I expect, they are a cheap alternative and dont have check valves fitted (the old set below, not confirmed this yet but the ports on the bottom between the hose fittings are possibly check valves) the bucher valves have them fitted and my old ones as of the same style. Would this be a plausible thought.
I think possibly I know the reason my spool valves aren't doing what I expect, they are a cheap alternative and dont have check valves fitted (the old set below, not confirmed this yet but the ports on the bottom between the hose fittings are possibly check valves) the bucher valves have them fitted and my old ones as of the same style. Would this be a plausible thought.
They're not check valves. There possibly some form of blanking cap from manufacturing, but immediately below those caps is the drilling for the studs that hold all the slices together, so there won't be any oil immediately below them.
Although the cap just above your thumb, and the bigger cap on the opposite end of that slice would indicate it's not a standard slice, but looking at the style of cap, I'd guess it's more likely to be a pressure relief valve just for that.
Is that the slice for the lift, or the tilt?
Although the cap just above your thumb, and the bigger cap on the opposite end of that slice would indicate it's not a standard slice, but looking at the style of cap, I'd guess it's more likely to be a pressure relief valve just for that.
Is that the slice for the lift, or the tilt?
chrismac
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Looking for some assistance again if possible,
I have bought a 3 slice Kontak spool valve of ebay, it does not have the tapped hole for the HPCO (power beyond or pressure carry over) having stripped it tonight as I only need 2 slices, would I be correct thinking if I drill and tap the end cover and buy the HPCO adaptor I am good to go?
Drill the centre port on this.
so it fits into this hole
Possibly the adaptor to fit, will need to see if the length of the machined part to the O-ring sits in the port to seal it up, as I think thats what it does, stopping flow to either the return or tank.
drilled and tapped end cover
out of interest what are these poppet valves for, these are under the threaded rod holding the whole thing together
due to the lack of information I can find what are these things for under the leavers, they screw in and have an O-ring on the end, like a plug or something.
O-ring was missing from this one.
Thanks
I have bought a 3 slice Kontak spool valve of ebay, it does not have the tapped hole for the HPCO (power beyond or pressure carry over) having stripped it tonight as I only need 2 slices, would I be correct thinking if I drill and tap the end cover and buy the HPCO adaptor I am good to go?
Drill the centre port on this.
so it fits into this hole
Possibly the adaptor to fit, will need to see if the length of the machined part to the O-ring sits in the port to seal it up, as I think thats what it does, stopping flow to either the return or tank.
drilled and tapped end cover
out of interest what are these poppet valves for, these are under the threaded rod holding the whole thing together
due to the lack of information I can find what are these things for under the leavers, they screw in and have an O-ring on the end, like a plug or something.
O-ring was missing from this one.
Thanks
Last edited:
chrismac
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I hope to keep things tidy and not start a new thread with this hydraulic issue,
I have now got my spool valve fitted and I thought it was doing what it should, loader going up and down as expected, 3 pt linkage lifting as expected..... until I put the finishing mower on it yesterday, it would not lift it all the way up, it just cleared the ground, if I share how its plumbed in can someone confirm its as it should, I believe it is unless I am missing something,
I have the HPCO completing the circuit on the tractor hydraulics (same as previous spools fitted) allowing the arms to lift,
Below I have the pressure line from the pump (through a previous spool valve under the seat) to the IN port, the OUT port is dumping back to the tank through the spool under the seat.
Under the seat there is a blanked off spool valve, which used to have rear spools on it but the pipework was too rusty to refit, I just blanked the ports, The red fitting is from the pump, pressure line, the blue fitting goes to the IN on the loader spools, the new yellow hose tucked in at the back is from the OUT port on the loader spools, with the top yellow spool the tank return, this is all plumbed as working with the 2 previous spools but now the 3 pt linkage seems to have no power to lift, but lifts its own weight no problem,
I did read that the first PRV in the system can be the main one (no idea if that is the case or not) but even if this is the case the loader seems to have plenty power as I was heaping rubble yesterday and it was working fine, I unscrewed the cap of the PRV to see what was under there and its just a spring so I am guessing its a preset type, or maybe need totally unscrewed to set, I did not have any time to go any further.
Any advice greatly appreciated.
I have now got my spool valve fitted and I thought it was doing what it should, loader going up and down as expected, 3 pt linkage lifting as expected..... until I put the finishing mower on it yesterday, it would not lift it all the way up, it just cleared the ground, if I share how its plumbed in can someone confirm its as it should, I believe it is unless I am missing something,
I have the HPCO completing the circuit on the tractor hydraulics (same as previous spools fitted) allowing the arms to lift,
Below I have the pressure line from the pump (through a previous spool valve under the seat) to the IN port, the OUT port is dumping back to the tank through the spool under the seat.
Under the seat there is a blanked off spool valve, which used to have rear spools on it but the pipework was too rusty to refit, I just blanked the ports, The red fitting is from the pump, pressure line, the blue fitting goes to the IN on the loader spools, the new yellow hose tucked in at the back is from the OUT port on the loader spools, with the top yellow spool the tank return, this is all plumbed as working with the 2 previous spools but now the 3 pt linkage seems to have no power to lift, but lifts its own weight no problem,
I did read that the first PRV in the system can be the main one (no idea if that is the case or not) but even if this is the case the loader seems to have plenty power as I was heaping rubble yesterday and it was working fine, I unscrewed the cap of the PRV to see what was under there and its just a spring so I am guessing its a preset type, or maybe need totally unscrewed to set, I did not have any time to go any further.
Any advice greatly appreciated.
I take it the 3pt linkage is the last thing to get the hydraulic feed, after it's passed through the two spool valve blocks?
Sounds like the loader spool isn't actually giving you full HPCO pressure, so when the linkage is loaded, the fluid is bypassing somewhere.
Sounds like the loader spool isn't actually giving you full HPCO pressure, so when the linkage is loaded, the fluid is bypassing somewhere.
It could do.
Usually the PRV is at the input to the spool block, so anything after that input will be protected by that PRV (unless there's one further upline that's set lower).
The best test is this situation, would be to put a pressure gauge on a loader output, then on the HPCO from the loader spool block and load the linkage up.
If the HPCO output gives a lower reading than a slice output, then something is bypassing within the spool block. If it's the same, then it's PRV doing it's job.
chrismac
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Okay so I have full pressure at the loader spools,
Ticking over on the 3pt linkage a lot less,
If I give it some revs the pressure increases and I am able to lift the mower, but thats not how it used to operate, its only increasing 200 psi.
I am wondering if the return line is taking over, do I need if they are even a thing to add a restrictor in line on the return line to assist in diverting the oil down the HPCO.
Chris
Ticking over on the 3pt linkage a lot less,
If I give it some revs the pressure increases and I am able to lift the mower, but thats not how it used to operate, its only increasing 200 psi.
I am wondering if the return line is taking over, do I need if they are even a thing to add a restrictor in line on the return line to assist in diverting the oil down the HPCO.
Chris
