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Discussion Starter #1
Hey Folks,
Wondering if anyone has done this, or has the knowledge of the 455 hydraulic circuit to help me design a PB kit.

I will be installing a cat-1 3PH on the tractor.... and here is what I am looking for: PB operation for a log-splitter, on the back of the tractor. Exactly the same setup and operation as the 2305 PB kit used for the backhoe or other implements like a splitter. On the 2305, all other functions remain operational, with the PB in use or not in use. In other words, the PB kit does not disable or disrupt any other hyd circuit. I am looking for exactly the same behaviour for the 455. Understanding that when the PB circuit is in active use, hydraulic flow rate will be split between it, and any other hydraulic circuit in use concurrently...

In searching the forum, I found only 1 useful link that talked about a PB outlet on the power-steering valve. Not sure I want to do that if the power steering system has a separate hydraulic circuit or if it operates at a lower pressure etc.
From what I found on the "interweb", it looks like there is only 1 hyd output from the transmission charge pump, and it goes to the PS steering pump, and from there it has T and goes to the 2-spool valve (see pic below). But the diagram is cluttered in that area so it's hard to tell.
Is there a PB output port on the PS valve?... is that the best one to use to get max flow and max pressure?... if not there, is there one on the 2-spool valve?.... or is there a port on the transmission itself I could use?...

On the 2305, the PB hose set needs to be connected together (male/female coupling) if not in use, because of continuous flow in that line. To me it almost sounds like it's connected in series with the other hyd circuits?... or am I understanding that wrong?

I understand the physics of hydraulics and am familiar with components, but I'm a novice in hydraulic-circuit design / architecture.
Looking for help and guidance.

 

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AKA Moses Lawnagan
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Will you be operating the log splitter's cylinder off the hydraulics of the tractor? The 1-series (2305 is part of that family, albeit older) hydro pump operates at substantially higher pressure than the big GT's do. Will the lesser pressure of the 455 be an issue?
 

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Discussion Starter #3
yea - that's the plan - to use the tractors' built-in pump.

Realize its only 1000PSI compared to 1900 for the 2305... i want to give it a shot since the wood I'm splitting is fairly easy to split so not having full pressure should be OK.....

Additionally, this is only the backup plan, as the 2305 would be the primary tool.... but as is the case at the moment, my 2305 is up north for next 2 months, and I need to split some wood.....

cheers!
 

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The K92 has an integral implement relief valve as part of the charge pump circuitry. As such, there is no need for a power beyond kit for the spool valve set. The pump flow goes to a priority flow diverter which splits off a dedicated approximately 2 gpm of the total flow specifically for the power steering. The balance of the available flow goes to the spool valve set.

That makes your project easy-peasy. No power beyond kit needed. Insert your new spool valve set into the return line from the original valve set.

> Original spool valve set > New spool valve set > Return to tank

Then run the work lines as required.

The circuitry is bit different in the 2305 in that the relief valve is integral with the spool valve. That situation requires the power beyond kit since the relief valve requires a dedicated return line back to tank. The return side of that valve is a largish chamber that incorporates both the return line port and the power beyond port. The power beyond kit seals off part of the chamber for the relief valve to dump excess pressure back to tank while allowing the flow to continue though for work beyond when the pressure is not excessive.

The charge system is set for 995 psi +/-72 psi as it comes from the factory. Max pressure allowed at the test port is 1502 psi.

With a 3.5" cylinder, you do not want any knots in the blocks at 1000 psi, and largish (over 12" in diameter) maple or birch may give you a hard time for splitting. Splitter head will move slowly, but most wood will split with a fairly short stroke. Birch is quite stringy and will usually require full cylinder travel, or an axe, to finish.

The auxiliary system on my GT will flow at about 2/3 throttle what yours will flow at WOT. The pressure is set for 1500 psi. That auxiliary system is totally separate from the hydro and is primarily for the loader, but the relief is set for the splitter.

I found the service manual for the K92 (with the hydraulic schematics) by searching " tuff torq k91 service manual ".

Hope your 2305 isn't snow bound before you get back to it! How far north?
 

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Deere has a rear hydraulic outlet kit for the 455 which is kit BM17939. If you can't find one or it will not do what you need might want to try Auxiliary Hydraulics in Tallahassee, FL www.auxhyd.com

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Discussion Starter #6
Deere has a rear hydraulic outlet kit for the 455 which is kit BM17939. If you can't find one or it will not do what you need might want to try Auxiliary Hydraulics in Tallahassee, FL Welcome to Auxiliary Hydraulics - If it didn't come with it, add it!

Sent from my Moto Z (2) using MyTractorForum Free App mobile app
Ya - saw that - thanks!... this kit connects to the existing spool valve and is controlled by one of the levers.
I am looking for power-beyond, which is essentially a full-time hydraulic fluid flow/pressure supply line. As if I wanted to connect another spool valve (which essentially is what I do when I connect the splitter)
 

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Discussion Starter #7
The K92 has an integral implement relief valve as part of the charge pump circuitry. As such, there is no need for a power beyond kit for the spool valve set. The pump flow goes to a priority flow diverter which splits off a dedicated approximately 2 gpm of the total flow specifically for the power steering. The balance of the available flow goes to the spool valve set.

That makes your project easy-peasy. No power beyond kit needed. Insert your new spool valve set into the return line from the original valve set.

> Original spool valve set > New spool valve set > Return to tank

Then run the work lines as required.

The circuitry is bit different in the 2305 in that the relief valve is integral with the spool valve. That situation requires the power beyond kit since the relief valve requires a dedicated return line back to tank. The return side of that valve is a largish chamber that incorporates both the return line port and the power beyond port. The power beyond kit seals off part of the chamber for the relief valve to dump excess pressure back to tank while allowing the flow to continue though for work beyond when the pressure is not excessive.

The charge system is set for 995 psi +/-72 psi as it comes from the factory. Max pressure allowed at the test port is 1502 psi.

With a 3.5" cylinder, you do not want any knots in the blocks at 1000 psi, and largish (over 12" in diameter) maple or birch may give you a hard time for splitting. Splitter head will move slowly, but most wood will split with a fairly short stroke. Birch is quite stringy and will usually require full cylinder travel, or an axe, to finish.

The auxiliary system on my GT will flow at about 2/3 throttle what yours will flow at WOT. The pressure is set for 1500 psi. That auxiliary system is totally separate from the hydro and is primarily for the loader, but the relief is set for the splitter.

I found the service manual for the K92 (with the hydraulic schematics) by searching " tuff torq k91 service manual ".

Hope your 2305 isn't snow bound before you get back to it! How far north?

Awesome thanks for all your help!... and the links to the manuals!!

I found this on the web (a page out of TM1517 - tech manual for the 425/445/455), which shows the k92, but then also shows the rest of the circuit in the tractor.



So the transmission pressure rail is regulated by the charge pressure relief valve (set at 924PSI), but the charge pressure control valve is set to 284PSI, and that pressure goes to the power steering valve, and then daisy chains to the main spool valve?... which then runs at 284PSI?... that's it?... or does that valve remain open (no flow) unless the pressure goes above 284?...

would a T-connection on the pump output, and T-connecting to the return line give me better pressure and flow - due to fewer components in-line that reduce flow at pressure?

is a T-connection easier to make (and costs less) than a straight connection to an available port on some valve or pump itself?

When you say this:
The pump flow goes to a priority flow diverter which splits off a dedicated approximately 2 gpm of the total flow specifically for the power steering. The balance of the available flow goes to the spool valve set.​
I think that's what the 2305 has, since it has a noted 2-flow rates: for power steering and for spool valve... but the 455 has a single port for both..... no?...
455 = 4.65gpm / 1000psi
2305 = pump flow 2.9, steering flow 2.3, total flow 5.2 (sum of the 2), split by a proportioning valve

So for the 2305 power beyond - does PB bypass the proportioning valve and provides the 5.2 total?.... or does it provide just the pump qty of 2.9.
if the latter, then the 455 should cycle the splitter faster than the 2305: ie 4.65gpm vs 2.9gpm

sorry for all the questions.....

the 2305 is about 120miles north of me, and down 10 mile really rough dirt road, across a wonky bridge, and 1 more mile along a rough ATV trail. it's a good 3.5-4hr ordeal to get it there or back. I fabbed up a heavy skid plate for the tranny, as the paths have lots of rocks protruding from the ground.
I need to move some dirt there, and I put a good dent in it yesterday, but had to come back before i finished. Top 2 feet is sand. Below it is rock-hard dry silt / clay. The BH with the 8" bucket struggled to sink in 50% of the 2 teeth-only (not bucket) into it... had to scratch it back and forth to have the teeth bite in a bit / loosen it up... then could begin to get the bucket into it to scoop it out.... 2+ minutes of scratching and scooping to get at best a half of an 8" bucket of soil excavated. I need to move 4-5 yards this way. I almost need a thin subsoiler bar instead of the bucket, to get more penetration pressure to break it up, then switch to bucket to excavate.
needless to say, I will be bringing another can of diesel with me next time I go up.

cheers!
 

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Awesome thanks for all your help!... and the links to the manuals!!

I found this on the web (a page out of TM1517 - tech manual for the 425/445/455), which shows the k92, but then also shows the rest of the circuit in the tractor.



So the transmission pressure rail is regulated by the charge pressure relief valve (set at 924PSI), but the charge pressure control valve is set to 284PSI, and that pressure goes to the power steering valve, and then daisy chains to the main spool valve?... which then runs at 284PSI?... that's it?... or does that valve remain open (no flow) unless the pressure goes above 284?...
The charge pressure control stops fluid flow to the implement lift and power steering until such time as the pump flow exceeds the needs of the hydro motor and control circuit for the PTO. This takes a fraction of a second after starting the engine unless there is a big (read expensive) problem in the hydro. Once charge pressure (284 psi) is established, the charge pressure control valve opens to allow the excess flow to move on to the power steering/implement lift and the charge pressure relief valve (or implement relief valve, if you prefer) becomes the pressure control at 924 psi.

The full flow from the charge pump, minus what is needed to keep the hydro fully charged with fluid and to service the PTO clutch and brake, gets delivered to the power steering/implement lift circuit with a relief setting of 924 psi.

would a T-connection on the pump output, and T-connecting to the return line give me better pressure and flow - due to fewer components in-line that reduce flow at pressure?
In the primary circuit of an open center hydraulic system, a Tee opens a direct path to the reservoir. Nothing will work, including the hydro if the Tee is directly after the pump. Strike the next sentence.

is a T-connection easier to make (and costs less) than a straight connection to an available port on some valve or pump itself?

When you say this:
The pump flow goes to a priority flow diverter which splits off a dedicated approximately 2 gpm of the total flow specifically for the power steering. The balance of the available flow goes to the spool valve set.​
I think that's what the 2305 has, since it has a noted 2-flow rates: for power steering and for spool valve... but the 455 has a single port for both..... no?...
455 = 4.65gpm / 1000psi
2305 = pump flow 2.9, steering flow 2.3, total flow 5.2 (sum of the 2), split by a proportioning valve
You are correct.

So for the 2305 power beyond - does PB bypass the proportioning valve and provides the 5.2 total?.... or does it provide just the pump qty of 2.9.
if the latter, then the 455 should cycle the splitter faster than the 2305: ie 4.65gpm vs 2.9gpm
No. The PB is a separate entity after the power steering valve and is simply a chamber separation item that allows the relief valve incorporated in the loader control valve to act independently for a flow path directly back to tank. The flow available to the control valve is also available to additional valve sets down stream. In this case, 2.9 gpm.

Yup, the 455 has more usable flow and the splitter will be faster, just not as strong with its lower pressure.

sorry for all the questions.....
No problem. It just took a while to figure out how to answer them.

the 2305 is about 120miles north of me, and down 10 mile really rough dirt road, across a wonky bridge, and 1 more mile along a rough ATV trail. it's a good 3.5-4hr ordeal to get it there or back. I fabbed up a heavy skid plate for the tranny, as the paths have lots of rocks protruding from the ground.
I need to move some dirt there, and I put a good dent in it yesterday, but had to come back before i finished. Top 2 feet is sand. Below it is rock-hard dry silt / clay. The BH with the 8" bucket struggled to sink in 50% of the 2 teeth-only (not bucket) into it... had to scratch it back and forth to have the teeth bite in a bit / loosen it up... then could begin to get the bucket into it to scoop it out.... 2+ minutes of scratching and scooping to get at best a half of an 8" bucket of soil excavated. I need to move 4-5 yards this way. I almost need a thin subsoiler bar instead of the bucket, to get more penetration pressure to break it up, then switch to bucket to excavate.
needless to say, I will be bringing another can of diesel with me next time I go up.

cheers!
That's still a fair jaunt south of me. Around the Kawartha's?

Hmm. Sounds like a bit of CIL silly putty would be more effective for the ground breaking ceremony. Know anybody in that game? Any rock work in the neighbourhood?
 

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Discussion Starter #9 (Edited)
In the primary circuit of an open center hydraulic system, a Tee opens a direct path to the reservoir. Nothing will work, including the hydro if the Tee is directly after the pump. Strike the next sentence.
ok so a parallel path (ie T connection) is no good. For this to work, it needs to be a series connection then - like you said. Being a series connection I guess there is no benefit where in the circuit it is installed, except that up stream means it will get 1st priority, and down stream (in the return path for example) it will get last priority right?

But the return paths are all T connected in the 455 circuit, so if for example I am making the power steering work, the existing spool valve gets nothing?... in the diagram for the 455, the pressure line from the pump comes into the power steering valve port under the label P and then is connected back out (label PB) and routes to the spool valve. The existing spool valve is open center no?... which would mean power-steering wont get anything while the spool valve is neutral (in open center) position?....


Our place is near the south end of Muskoka Lakes - due west of Gravenhurst.
Interestingly, where I am digging, the rock is far enough down that it's not in the way.... I got lucky. Unfortunately I dont know anyone who can help me in terms of using "chemical power" to move soil in miliseconds - so I'm stuck with the manual process... oh well... give the BH a workout....
 

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ok so a parallel path (ie T connection) is no good. For this to work, it needs to be a series connection then - like you said. Being a series connection I guess there is no benefit where in the circuit it is installed, except that up stream means it will get 1st priority, and down stream (in the return path for example) it will get last priority right?
Close, but not quite. Open center means constant flow. The fluid going through a valve to do work has to come back to the valve at the same rate of flow and continues down stream. Where the problem lies is with the pressure. Pressures are additive, meaning that, for instance, with a 1000 psi relief pressure, if the power steering requires 500 psi to turn the wheels, there is only 500 psi left before the relief pops to do other work. If the additional work requires 600 psi, the relief pops and you're done until the pressure for one or the other activity ceases or the work can be accomplished at a lower pressure.

In most cases, this just means that steering the tractor while stopped and lifting a payload at the same time will cause a momentary loss of flow as it is dumped over the relief until either you quit turning the steering wheel, or quit raising the load.

But the return paths are all T connected in the 455 circuit, so if for example I am making the power steering work, the existing spool valve gets nothing?... in the diagram for the 455, the pressure line from the pump comes into the power steering valve port under the label P and then is connected back out (label PB) and routes to the spool valve. The existing spool valve is open center no?... which would mean power-steering wont get anything while the spool valve is neutral (in open center) position?....
The circuitry inside the hydro is a different proposition. One branch of the Tee is blocked by the charge relief valve, and the other is blocked by the charge pressure control valve. In the diagram, the straight through branch is blocked by the hydro motor which has a limited acceptance of fluid that is normally considerably less than the flow available from the charge pump. Once pressure has built high enough, the charge pressure control valve opens and flow becomes available to the p/s and implement lift circuitry. The process is almost instantaneous from engine start to open implement lift circuit. If the charge pump is full of fluid and the hydro pump and motor are both empty, it takes 6 engine revolutions to fill the pump and motor and another one or two to fill the connecting passages. In the time that you can move your hand from the key to a lift valve handle, all systems are set to go.

Too bad about the shortage of "chemical power" engineers. Our next door neighbor at camp was a cook for a lumber company's bush camp. One of his acquaintances was just such an engineer and several large stumps became non-problems in short order.
 

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Discussion Starter #11
Close, but not quite. Open center means constant flow. The fluid going through a valve to do work has to come back to the valve at the same rate of flow and continues down stream. Where the problem lies is with the pressure. Pressures are additive, meaning that, for instance, with a 1000 psi relief pressure, if the power steering requires 500 psi to turn the wheels, there is only 500 psi left before the relief pops to do other work. If the additional work requires 600 psi, the relief pops and you're done until the pressure for one or the other activity ceases or the work can be accomplished at a lower pressure.

In most cases, this just means that steering the tractor while stopped and lifting a payload at the same time will cause a momentary loss of flow as it is dumped over the relief until either you quit turning the steering wheel, or quit raising the load.



The circuitry inside the hydro is a different proposition. One branch of the Tee is blocked by the charge relief valve, and the other is blocked by the charge pressure control valve. In the diagram, the straight through branch is blocked by the hydro motor which has a limited acceptance of fluid that is normally considerably less than the flow available from the charge pump. Once pressure has built high enough, the charge pressure control valve opens and flow becomes available to the p/s and implement lift circuitry. The process is almost instantaneous from engine start to open implement lift circuit. If the charge pump is full of fluid and the hydro pump and motor are both empty, it takes 6 engine revolutions to fill the pump and motor and another one or two to fill the connecting passages. In the time that you can move your hand from the key to a lift valve handle, all systems are set to go.

Too bad about the shortage of "chemical power" engineers. Our next door neighbor at camp was a cook for a lumber company's bush camp. One of his acquaintances was just such an engineer and several large stumps became non-problems in short order.
Thanks again for all the detail... i'm learning!....

In the last post, you elaborated on what happens inside the hydro. My question was actually about the "outside" the hydro....
If you look at the page I posted (reposted below) - begin to trace the path of the fluid on the high-pressure port on the hydro, and go downstream from there.....

So to reiterate the questions:
1. the return paths are all T-connected in the 455 circuit [outside the hydro], so if for example I am making the power steering work, the existing spool valve gets nothing?... or at least only gets the left-over flow and pressure that the power steering valve doesnt use?
2. in the diagram for the 455, the high pressure line from the hydro comes into the power steering valve port under the port label P and then inside the valve it is connected back out (port label: PB) and from there goes to the spool valve. I guess the power steering valve is not open-center?... because if it was, the spool valve would get zero pressure if steering is unused... no?.... The existing spool valve is open center I think?... which would then mean power-steering won't get any pressure, because all the fluid flows in the power steering port P, and right back out the port PB, and on to the spool valve which is open center, which means the fluid just returns to the reservoir via the return line?.... so how does the Power steering valve ever get pressure?

 
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