Power Beyond or HPCO valve help needed

[bbutcher]

I have a Satoh S650G, a.k.a. "Bison" with a front end loader (FEL). The tractor has a hydraulic system that raises the 3 point hitch. There is a triangular shaped plate under the seat that has two hydraulic lines connecting to the FEL (a pressure line and a return line) control valve. Today I connected my backhoe attachment by adding tees in the lines, so the backhoe control valve is in parallel with the FEL control valve. As connected neither the FEL nor the backhoe operate correctly. It appears that when the control valve for either the FEL or hoe is centered the hydraulic fluid is bypassed from the high pressure line to the return line, thus it never develops pressure enough to operate the cylinders. I assume this is called an open control valve?

If I open any one valve for the FEL, and simultaneously open any one valve for the hoe, both move correctly. As a temporary measure I tied the FEL raise/lower valve in the lower position, and once the FEL is all the way down, the hoe valves work correctly. Likewise I can tie any hoe valve open and once the associated cylinder reaches the end of travel, the FEL works correctly.

I have heard of a "power beyond" valve (also called "high pressure carry over") that I think will force both systems to work correctly together. I assume that somewhere inside the tractor hydraulic system is something similar since both the 3 point hitch and the FEL work together correctly. In fact the triangular plate mentioned above has 4 o-ring sealed ports, but two of them are just blocked off (never drilled) while the other 2 go to the FEL hoses (pressure and return). Does anyone know if I drilled holes and added 2 more hose connections to the blanked off ports to operate the hoe if this would solve the problem? I found Brendan Casey's description of the power beyond valve, but I don't understand just how to connect it if I found one. Do I need to modify my control valves to make them closed? From what I have read it is necessary to size the power beyond valve for the pump capacity, which is 4.1 GPM for my tractor.

Am I on the right track here, or is there something else I should do? http://www.tractorbynet.com/forums/images/smilies/confused.gif
Bob

 

[J_J]

Yes. you should size the valve for the GPM's. You can not connect the valves in parallel

I believe the pressure line from that plate, should go to the input of the BH valve, and the BH out should go back to the return on the plate. Can you show pictures of the plate, and was anything connected before?

All open center valves should be in series.

 

[kennyd]

Welcome to TBN


Hydraulic fluid, like electricity will "take the path of least resistance". So when you added the valve with the Tee's, and operated the FEL valve since there was resistance added the fluid just went through the newly added hoe valve, and vise/verse. Make sense?

All new valves MUST be added in series, this is where the PB (power beyond) comes into play. Every tractor is different, so adding pictures of your's will help us help you. Now many hoses are connected to your FEL valve, 6 or 7? IS there a port marked PB, BY, or BYD on it?

Also, do some searching 'round here...there are LOTS of threads describing how to add a valve or "remote".

 

[J_J]

KennyD, I sure wish you would unblock me, as you are repeating a lot of my post. I believe it is a good thing that people want to help others with problems, however, these people that have people blocked out , is not a good thing, and are just repeating the data already given. It's like they think we don't exist. I don't have you blocked out, and read all your post.

Since he has me blocked out, he probably can't read this.

 

[jake98]

Since he has me blocked out, he probably can't read this.

Some of us thick skulls need to hear things twice anyway..

 

[bbutcher]

Thank you KennyD and JJ for your replies. I did find a website saying I should connect open center valves in series, so I did that. Now it works more or less correctly, exept the FEL tends to raise slowly when I use the BH. I am also experiencing leakage somewhere in the spool valve for the FEL. I think the problem is related to having the output of the FEL spool valve at high pressure instead of going back to the tank, but I may just need to replace some seals. I need to identify the power beyond port if one exists on the FEL spool valve. I did find some info on the Prince website that may be helpful in getting it connected correctly. I will try to get some photos and maybe some more details on the spool valve if it doesn't snow today.

 

[J_J]

If the FEL valve is the first valve inline, and you operate the levers full up or down, you could use all the hyd flow from the pump, and the 3pt would get none. If using only some of the lever travel, some of the hyd fluid would flow through the open center valve, through the tank port, and back to the 3pt, and both would work, only slower.

If you only use the 3pt, then the complete hyd circuit from pump to the 3pt is high pressure, depending on the load.

The only time the out/tank port has high pressure is when you are using the 3pt, which means that the FEL valve, hose and 3pt valve are seeing the high pressure.

This is why, when someone is replacing a FEL valve, to select a valve that will handle the high pressure on the out port of the FEL. Tank ports are usually low pressure.

The BH valve should be in series and before the 3pt. This will cause all the valves in the circuit to see high pressure if the 3pt is used. If you disconnect the BH, then you need to jumper the connections for the BH, to provide a complete path for fluid flow through the 3pt.

 

[bbutcher]

Thank you for the info JJ. I have more information now. The 3 point system is plumbed in as part of the tractor and it is not easy to access the hydraulic line between it and the pump. The fluid from the 3 point goes to the "block" I mentioned previously, shown in the photo below. The two lines from this block originally went to the FEL control valve, a Gresen 2702 which seems to not have a power beyond port (photos below) unless the plugged port shown is it.

I have re-plumbed the system to use the oil coming from the 2702 return as the inlet for the BH. All systems function correctly, including the 3 point, other than the oil leak in the 2702 and the slow movement of the FEL while using the BH. When I remove the BH, I will install a short hose between the two quick connect fittings to route the oil to the FEL.

It appears that maybe I should route the oil to the BH first to avoid high pressure on the outlet port of the 2702. The BH control valves may have a power beyond port, but I do not have good photos of them, and I will need to remove some panels to even get a manufacturer or model number for them. The BH is a Kelly B-750 and the diagram shows connecting to a power beyond port for the FEL (shown below).

 

[MtnViewRanch]

Just want to give a friendly warning, in your pictures it looks as though you are using standard water pipe fittings. If they are water pipe fittings, they are not rated for the hydraulic pressure that you are running through them. I know that this has been done for many years and sometimes all is fine, just wanted you to be aware of the possible problems that may occur.

 

[kennyd]

Just want to give a friendly warning, in your pictures it looks as though you are using standard water pipe fittings. If they are water pipe fittings, they are not rated for the hydraulic pressure that you are running through them. I know that this has been done for many years and sometimes all is fine, just wanted you to be aware of the possible problems that may occur.

Good catch MVR:thumbsup:

Regular iron pipe fittings are usually rated for only 150 or 300 PSI-especially the ones now that are cast on China. These fittings can see 3000+ PSI with shock loads on a loader or backhoe.