Yanmar 336D FEL only works when 3 point is raised to max and straining the engine!?

[bulldogmack407]

Hello, i tried solving this problem on other forums but had no luck. I bought a Yanmar 336D for $1000 recently. The tractor is in decent shape and runs/operates great. However the tractors FEL will not operate unless you raise the 3 point hitch beyond MAX to the point where you can hear the engine bogging down a little. You can also see one of the lines going to the spool valve tense up. If you use the loader the engine tone returns to normal and the line is not tense until you stop using the loader or lower the 3 point. I replaced the spool valve that was on it when i got it however it did the exact same thing with the old one. The reason i replaced the old one was because it was cracked. There are 3 lines hooked to it besides the 4 ones for the loader cylinders. One of the lines just goes into the reservoir (trans housing) and the other 2 go to a block under the seat. I have spoken to several people and some have told me there should only be 2 lines not 3. I also have a power beyond valve on one of the lines. The only reason i installed the power beyond is because i was told with 3 lines i need it and with 2 you dont. I have included photos of the set up. On all the other forums i got alot of people telling me to cut the steel lines from the pump and plumb things in and people speculating. This machine has the factory loader on it so i know it will work somehow without re engineering the hydraulic system so please dont give me those answers. If you have one of these tractors could you please send me photos or show me where the lines go and tell me weather or not i need the power beyond valve. I love this tractor even with the issues it has at the moment and really want it working without issues.

Thanks

 

[J_J]

Your tractor is open center, so all valves go in series.

When adding valves, you need a valve with PB in order to pass fluid downstream.

All tank lines go to tank via a return line.

Your loader probably gets the fluid first, so it must have the PB adapter installed.

All other valves will be in series and need a PB port with adapter.

 

[bulldogmack407]

Your tractor is open center, so all valves go in series.

When adding valves, you need a valve with PB in order to pass fluid downstream.

All tank lines go to tank via a return line.

Your loader probably gets the fluid first, so it must have the PB adapter installed.

All other valves will be in series and need a PB port with adapter.

So if the loader is first then i was right to install a PB, the tractor always had this loader on it so the issue is not a loader being added or anything. That being said what could the problem be?

 

[Leejohn]

Why are there two hoses from loader valve going to same place?

 

[bulldogmack407]

No idea, this is the way it was set up when i got it. I am lost when it comes to where everything SHOULD go. I have emailed several people asking for photos of their tractor

 

[Leejohn]

Go to Prince Manufacturing Corporation Home Page and look at some of the drawings. See if you can find something like you have. You don't care a hole lot about what kind of valve you open, just look over the plumbing. I think it might be plumbed wrong.

 

[bulldogmack407]

Go to Prince Manufacturing Corporation Home Page and look at some of the drawings. See if you can find something like you have. You don't care a hole lot about what kind of valve you open, just look over the plumbing. I think it might be plumbed wrong.

I received a diagram with the loader valve from them. I hooked up the valve how the diagram showed and it was the same way the valve was installed before. A week ago i actually switched the two other lines (not the return-tank line) and it functions exactly the same.

 

[Leejohn]

What is it that the hoses are hooked to in the 1st picture.

 

[bulldogmack407]

Its some sort of hydraulic block bolted to the 3 point housing, there is a lever on top of it to increase or decrease the hydraulic speed.

 

[Leejohn]

Well it seems like your loader is working off of back pessure from the 3 pt and that is why it is only working with the 3pt lever all the way up. Your pic #2 is small and can't tell where the lines go. The 2 hoses that are coming back to loader valve in picture #1 just where do they hook up at the valve?