how to tie into PB

kenmac · Aug 25, 2011

my loader valve has a PB port. The way the Hydraulic lines connect on this tractor will I be able to use the PB port & still be able to operate the rest of the Hydraulics on my tractor ?

See pics of how loader lines are connected to loader valve

The High Pressure line is cut and routed through my loader valve ( High pressure) & out ( H.P.) for the rest of the Hydraulics on the tractor to operate.The High Pressure then (I assume) goes to the sump & returned on the suction line ( all tractors may operate like this I don't know) The current loader valve has a PB port which is plugged. The loader valve manual states, if I use the PB port it changes the loader valve from open center to closed. Do I need to keep the valve open center so the rest of my Hydraulics will operate ?

Thanks

J_J · Aug 25, 2011

How about some more pictures.

Can you describe your hyd flow more in detail, like pump, FEL valve, 3pt, tank, etc?

What does the QD supply?

Valves that have PB ports can be adapted to open center, PB, or closed center by using an adapter.

Your tractor is probably open center.

kenmac · Aug 25, 2011

J_J said:
How about some more pictures.

Can you describe your hyd flow more in detail, like pump, FEL valve, 3pt, tank, etc?

What does the QD supply?

Valves that have PB ports can be adapted to open center, PB, or closed center by using an adapter.The 1st pic is with loader not installer & a hose connected so, the tractor can operate without loader. These aren't pics of my tractor but, all yanmars are set up the same way for loader

Your tractor is probably open center.

what do you need me to describe about hyd flow, pumb, valve 3 pt ? I don't know what QD supply is

Yes the valve is set up as open center.From what I understand the valve Manual states if PB is used the loader valve becomes open center

J_J · Aug 25, 2011

The line going to the banjo fitting, is that your pump output? This would be a normal path with a FEL valve. Pump to FEL IN port, PB plug/screw installed, line from PB port to then to 3pt, and then to tank. The FEL OUT port would go to tank/reservoir.

[ I would definitively remove that QD set from the pump. ] Should something accidently cause the QD to unplug, the pump would probably blow up. Use a union or nipple to join the two hoses/lines.

Did you check or set the PRV on the FEL valve?

I would suggest plumbing in the FEL valve, and use QD's on the work ports, and leave the FEL valve on the tractor if removing the loader. .

kennyd · Aug 25, 2011

kenmac said:
The current loader valve has a PB port which is plugged. The loader valve manual states, if I use the PB port it changes the loader valve from open center to closed. Do I need to keep the valve open center so the rest of my Hydraulics will operate ?

Thanks

I never heard of anything like that before...PB setups are not used in CC systems. I think you are mis-reading the manual. Yes, the valve must remain OC.

kenmac · Aug 25, 2011

J_J said:
The line going to the banjo fitting, is that your pump output? This would be a normal path with a FEL valve. Pump to FEL IN port, PB plug/screw installed, line from PB port to then to 3pt, and then to tank. The FEL OUT port would go to tank/reservoir.

Did you check or set the PRV on the FEL valve?

.

Yes the banjo fitting is the pump out put. There is a plug in the pb port as of now.Pump out put (H.P.) is on the inlet port of the fel valve.On the Out port on fel valve high pressure continues to the rest of the tractor hydraulics power shift & 3 pt B-4 dumping into the sump (or transmission) I'm not sure these yanmar FEL valves are plumbes like other tractors. I didn't check or set the PRV on the FEL valve.Just had this loader installed about a month ago. The dealer may have set or checked it

kenmac · Aug 25, 2011

kennyd said:
I never heard of anything like that before...PB setups are not used in CC systems. I think you are mis-reading the manual. Yes, the valve must remain OC.

What is a CC system ? the valve I have is a Dinoil valve for the FEL

On the diagram it shows Valve is shipped open center for closed center applications replace item 1 9which is the plug in the PB port0 . with item 2 which looks like a fitting and a hose for PB

J_J · Aug 25, 2011

CC is closed center, whereby the fluid does not flow continuously through the valves. It is usually used with a variable speed pump.

It depends on the FEL valve you have now, as to the use of the PB port. Some valves will not withstand pressure on the out port of more than 500 psi, and if you have a PB port, I would get the adapter for PB and use that port to feed the 3pt. The OUT from the loader valve should go to tank.

What brand name of the loader valve?

Check with the parts dept for the right part.

kenmac · Aug 25, 2011

a pic of the manual. Hope you can read it.

J_J · Aug 25, 2011

Yes, I can read it, and it says that the valve comes as open center, and if you want PB, to purchase and install the PB sleeve.

What the PB sleeve does is to separate the main gallery and OUT port and lets the hyd flow pass downstream through the PB fitting for additional valves or just to 3pt.

The cyl's expended fluid only goes to the OUT port, and most times the out ports go to tank.

kenmac · Aug 25, 2011

J_J said:
Yes, I can read it, and it says that the valve comes as open center, and if you want PB, to purchase and install the PB sleeve.

What the PB sleeve does is to separate the main gallery and OUT port and lets the hyd flow pass downstream through the PB fitting for additional valves or just to 3pt.

The cyl's expended fluid only goes to the OUT port, and most times the out ports go to tank.

Thanks for pointing that out. I know 0 about hydrauics. So, that means I purchase a sleeve for the PB port Then a hyd hose then connect to a valve for a grapple ?? & my loader valve will still have open center ? correct ?

On my yanmar the out port does go to the tank eventually after it powers the power shift & the 3 pt

SSdoxie · Aug 25, 2011

The picture digagram is just showing the 3 different variations available, open center w/PB, Open center w/o PB, & closed center. You want it to look like th top picture. As JJ mentioned before, do not use the quick couplers go to or out of the valve. Mount the valve so it stays with the tractor if loader is taken off then use quick couplers on the 4 hoses going to the cylinder circuits.

kenmac · Aug 25, 2011

thank you guys. The pics of the tractor isn't mine. It's 1 I found on the net to show how these are connected. My tractor lines are hard piped (no quick connects) I will call the dealer & see if I can purchase the P B sleeve

Brad_Blazer · Aug 25, 2011

kenmac said:
On my yanmar the out port does go to the tank eventually after it powers the power shift & the 3 pt

The way you describe the out port it is routed where power beyond should be i.e. it wasn't installed correctly. Out ports are not designed to be pressurized like the power beyond port. Also, separating the out and power beyond ports allows the relief function to work correctly. Hopefully you have a convenient port on your hyd. tank for the return (out) ports to be connected.

kenmac · Aug 26, 2011

Brad_Blazer said:
The way you describe the out port it is routed where power beyond should be i.e. it wasn't installed correctly. Out ports are not designed to be pressurized like the power beyond port. Also, separating the out and power beyond ports allows the relief function to work correctly. Hopefully you have a convenient port on your hyd. tank for the return (out) ports to be connected.

On my tractor & other yanmars that I have seen. The H.P. line from the pump is cut. From the pump H.P. the line goes to the inlet of the loader valve. The out port of the loader valve continues on ( I assume still H.P. as there is not a regulator to cut the pressure after it exits the loader valve) to the 3 point part of the tractor. I guess at some point it returns to the sump or transmission

Brad_Blazer · Aug 27, 2011

The only difference between the way it is and the way it should be is that the loader valve should be set up for PB with the PB line feeding the 3ph and one more line going from the out port on the loader directly to the sump. If your transmission fluid is separate from the hyd. fluid the casting the lift arms come out of is typically the hydraulic sump.

The way the whole system works is that the hydraulic pump provides positive flow through all of the valves whenever the engine is running. This is sometimes called the power beyond loop. When a valve is actuated, it diverts flow to the working cylinder and for double acting cylinders the fluid on the other side flows back through the valve to the "out" port. Resistance to the cylinder moving causes high pressure in the loop from the pump to the working valve. When the resistance is too high or the cylinder reaches the end of it's stroke, the fluid has no place to go so a relief valve built into the control valve allows flow to pass to the "out" port at the relief pressure which is typically 2000-2500 psi. The simple relief valves used are affected by downstream pressure so if the out port is used as power beyond, valves in series that are operated simultaneously can theoretically cause pressures as high as the sum of their relief pressures. For example in your current setup if you operate the 3ph at the same time as the loader you can create this situation. I know it would be unusual to do that but it only has to happen once to damage the pump. According to experts I have talked to, it is also bad to even have the "out" port exposed to high pressure. That's why it is proper to use valves set up to separate the high pressure power beyond loop from the low pressure "out" ports which should return to the sump, possibly going through a filter along the way.

kenmac · Aug 27, 2011

I wish I knew how to fix it but, I don't . Like I said in my previous post all the yanmars I,ve seen are plumbed this way in this pic

( This isn't a pic of my tractor. it's another yanmar set up for loader) The small line on top is comming out of the pump. The rubber hose connects to the IN port on the loader valve. The small line on the bottom where the other end of the rubber hose connects . Is connected to the OUT port of the loader valve. My system is connected just like this http://www.hoyetractor.com/support/knowledgebase.php?article=58 system. If you were to take the aux. valve out of the pic . H.P. travels from pump through loader valve then out to 3 point

J_J · Aug 28, 2011

If your loader valve does not have a PB outlet, and you have been using the tractor for a while, You can use it as is, even though there could be high pressure built up in the valves at times. Any time you use the 3pt and hold the lever until the relief comes on, high pressure is reflected back through all the other valves.

If the out port has seen high pressure many times before, the valve can probably handle it. Also, just about all manufacturers say to route the OUT port to tank, and they also state the back pressure.

I believe enough data has been given here to make some logical decision about what to do.

If you use a valve with only an out port for the fluid exit, you take a risk, and it is your tractor, so do what you want.

Ductape · Aug 28, 2011

You are correct that many grey market tractors are pumbed this way when loaders are added. If the PB sleeve is available, I'd get it and plumb your next valve that way. If not, I'd use the out line to plumb your next function in line. Obviously, using the out is not the best way, but you have what you have.