LD1
Epic Contributor
Usually those block off plat or caps aren't really block off plates.
Its a place to add functions like the loader or a remote valve.
With the original plate on it....it would simply connect the two ports....not block them off. One port would be high pressure oil coming from pump, the other would be return (but not to tank) rather it is return to the 3ph control inlet.
So with no attachments....the 3ph plumbing is mostly internal. So think of that "cap" as a hydraulic hose couples right there that is feeding the 3ph. And changing the "cap" is like uncoupling the 3ph feed, and allowing you to feed something else like your loader first....and then tying the loader back in to feed the 3ph.
It's hard to understand just where all the hoses are going and routes without actually laying eyes on it and tracing the circuits in person.
But it your loader valve indeed has 7 hoses.....you DO have a P (supply);a T and a PB.
The supply is probably coming from that cap. Your loader works fine.
But as I said....you have two ways for oil to exit your loader valve.
1. It exits the PB port when the loader isn't being cycled.
2. It exits the T port when the loader is cycled.
You have the T port going back to the 3ph feed. Which is why it only works when you cycle the loader.
Since the original owner had a backhoe and never used the 3ph....dumping oil back to tank through the open center 3ph valve when using the loader was ok. And he used the PB loader port to go to the remote valve.
I don't think you posted pictures of the remote valve plumbing.
Ideally it will have 3 hoses to connect it. It should have it's supply coming from the PB of the loader....and it shall have its own PB port to feed the 3PH as well as a second tank or return.
The only things that can be TEEd together are the tank lines.
In an open center system you can never tee a P or PB line.
Right now.....if you want to omit that remote valve just to get working....follow the T hose coming off the loader valve and unhook it where it attaches to that "cap". Find a new place to dump it back to the hydraulic/transmission case. And take the hose currently going to the remote valve and put it on that "cap" where you just unhooked the tank line from
Its a place to add functions like the loader or a remote valve.
With the original plate on it....it would simply connect the two ports....not block them off. One port would be high pressure oil coming from pump, the other would be return (but not to tank) rather it is return to the 3ph control inlet.
So with no attachments....the 3ph plumbing is mostly internal. So think of that "cap" as a hydraulic hose couples right there that is feeding the 3ph. And changing the "cap" is like uncoupling the 3ph feed, and allowing you to feed something else like your loader first....and then tying the loader back in to feed the 3ph.
It's hard to understand just where all the hoses are going and routes without actually laying eyes on it and tracing the circuits in person.
But it your loader valve indeed has 7 hoses.....you DO have a P (supply);a T and a PB.
The supply is probably coming from that cap. Your loader works fine.
But as I said....you have two ways for oil to exit your loader valve.
1. It exits the PB port when the loader isn't being cycled.
2. It exits the T port when the loader is cycled.
You have the T port going back to the 3ph feed. Which is why it only works when you cycle the loader.
Since the original owner had a backhoe and never used the 3ph....dumping oil back to tank through the open center 3ph valve when using the loader was ok. And he used the PB loader port to go to the remote valve.
I don't think you posted pictures of the remote valve plumbing.
Ideally it will have 3 hoses to connect it. It should have it's supply coming from the PB of the loader....and it shall have its own PB port to feed the 3PH as well as a second tank or return.
The only things that can be TEEd together are the tank lines.
In an open center system you can never tee a P or PB line.
Right now.....if you want to omit that remote valve just to get working....follow the T hose coming off the loader valve and unhook it where it attaches to that "cap". Find a new place to dump it back to the hydraulic/transmission case. And take the hose currently going to the remote valve and put it on that "cap" where you just unhooked the tank line from