Hydraulic control valve

[kennyd]

I understand the in and out hookups now and again thanks for the help. The only issue I am trying to figure out now is the tank "T" port. I don't have a tank exactly. The pump pressure line goes directly to the pto and it sits on top of the transmission and I assume it dumps into the transmission via a hole between the two. The suction line comes out of the bottom of the transmission to the pump. There is no actual return line from the pto to the transmission. So, looking at the diagram from the Prince set up, I'm not sure where to run the "T" port to. Can I run it to the suction line or will that cause a vacuum when the control valve is in the neutral position and maybe cause creeping through the valve? When using the PB sleeve, do I still need the "T" port or will the cylinder return oil be routed to the PB port and I just plug the "T" port hole?

When using a PB equipped valve, You CANNOT plug the T or OUT port as it carries the "waste oil" from the work ports to the tank.

When you say:

The pump pressure line goes directly to the pto and it sits on top of the transmission

I take that it feeds the 3PH, so that is where you would plumb the PB port from the new valve to. Somewhere on you transmission should be a plugged port you could use as a return-to-tank port. What machine do you have?

 

[Gary Sweat]

Here are pictures of the tractor PTO lines and pump. If there's a place on the PTO that I can use for the return line please let me know. Thanks

 

[Gary Sweat]

Here are photos of the valve. If that helps?

 

[Gary Sweat]

Well, I got the valve figured out. This valve returns the cylinder oil to the PB port when the levers are moved. When the PB sleeve is installed all oil goes out this port and the tank port is blocked off. It also passes the pressure oil to this port when the levers are in neutral. So all I have to do is put the PB sleeve in and move the plug to the tank port and hook the PB port back up to the other side of the cut pressure line and everything should work fine. The valve came with the PB port plugged and that was what was confusing me. I didn't realize the hole between the PB and tank ports was making it look like the tank port was where the outflow was going.

Thanks to everyone who helped me on this. I really appreciate it.

 

[J_J]

Do not plug up the tank ports as that is the outlet for the cyl fluid that is expended. A return hose goes to tank/reservoir.

There is no pressure in the valve when in neutral. The fluid just passed through the valve for downstream operations. If no valves is operated, the fluid just makes a continuous loop from pump through the valves, to tank, with no pressure.

 

[Gary Sweat]

Well, I guess I'm back to square one. There is no return line on this tractor to tie into and no place that I can find to add a return line to without drilling a hole in the transmission and I don't think that is a good way to go. Maybe this valve is not going to work on my tractor and I will have to find a different kind. I'll try to find a picture of how the after market loaders hook up and see what type of valve they are using. I do know they say on their valves to cut the pressure line from the pump and route the pump side into the inlet port and run a line from the PB port to the other side of the cut pump line that goes to the 3pt hitch valve. They don't say anything about a tank line so there must be something different about their valves that I don't understand.

 

[J_J]

Every valve has to have an outlet that goes to tank/reservoir, and is stamped T. If the valve does not have a PB port, the expended fluid, from the cyl and the norm flow from the pump flows through the valve and out the return port, and normally goes to the 3pt, and then to tank.. All the fluid ends up in the tank/reservoir. There is a tank return somewhere on the tractor. The return hose could be adapted to go through the filler cap, if necessary.

 

[kennyd]

Well, I guess I'm back to square one. There is no return line on this tractor to tie into and no place that I can find to add a return line to without drilling a hole in the transmission and I don't think that is a good way to go. Maybe this valve is not going to work on my tractor and I will have to find a different kind. I'll try to find a picture of how the after market loaders hook up and see what type of valve they are using. I do know they say on their valves to cut the pressure line from the pump and route the pump side into the inlet port and run a line from the PB port to the other side of the cut pump line that goes to the 3pt hitch valve. They don't say anything about a tank line so there must be something different about their valves that I don't understand.

The kits that Ronald sells at Jinma Loader Valve sells do not use PB valves. Search in the Chinese and Yanmar tractor forums. You would need to keep the PB port plugged.

 

[Gary Sweat]

Every valve has to have an outlet that goes to tank/reservoir, and is stamped T. If the valve does not have a PB port, the expended fluid, from the cyl and the norm flow from the pump flows through the valve and out the return port, and normally goes to the 3pt, and then to tank.. All the fluid ends up in the tank/reservoir. There is a tank return somewhere on the tractor. The return hose could be adapted to go through the filler cap, if necessary.

J J, In the photos I posted, the port on the left of the valve is the PB and the right one is the tank port. There is a small hole between the two that connects them together. If I install the PB sleeve it will block the hole between the two ports and I am still stuck with the return line problem since this tractors pressure line goes directly into the 3pt valve which is mounted on top of the transmission and dumps the oil into the transmission via a hole between the two. There is no return line coming out of the 3pt valve that I can tie into. It is my understanding that it can damage the valve if the pump pressure gets into the tank port. Maybe I should go over to the Yanmar forum and ask if anyone can post a photo of how theirs are hooked up to help me understand what I need to do.
Thanks for the help and your patience.

 

[J_J]

You have a choice here, and that is to use the PB port, or not. If you choose to not use the PB port, then install the OC plug in the PB port, and use the T outlet to connect to the rear3pt. No extra hose needed.

If you choose to use the PB port, then you will have to find a way to get the fluid from the T port to tank. Either way will work, as long as the tank port will handle the high pressure. I would call the people you purchased the valve from, and ask then the question. Will the tank port on the new valve withstand high pressure.