John Deere 48 backhoe thumb hydraulis

[bigdan65]

Backhoe was on a JD 5205. The valve has a power beyond port so it has 3 lines 1 in and 2 out. Can I mount a valve on the backhoe for a thumb powered by the pb line then Tee the return into other return line? The backhoe is going on a JD 4500

 

[bigdan65]

Backhoe was on a JD 5205. The valve has a power beyond port so it has 3 lines 1 in and 2 out. Can I mount a valve on the backhoe for a thumb powered by the pb line then Tee the return into other return line? The backhoe is going on a JD 4500

I will try to clarify.
The backhoe valve has a power beyond adapter installed creating the 2 return lines. This was for JD 5105 & 5205.
My 4500 does not require the high pressure return line so instead of removing the power beyond adapter I want to feed a valve for a thumb. The valve will be mounted on the backhoe frame. New valve will not have power beyond.

Can I tee the original return line and the return line from new thumb valve together so I will only have 1 return going to tractor?

 

[ptsg]

Yes.

PB from the backhoe valve goes to IN of Thumb valve and you can just T the tank lines from the both valves and connect back to the tractor.

As long as the tank lines will dump directly to the tractor sump and won't feed anything else like a 3 pt valve or something, you're good to go.

 

[rScotty]

I will try to clarify.
The backhoe valve has a power beyond adapter installed creating the 2 return lines. This was for JD 5105 & 5205.
My 4500 does not require the high pressure return line so instead of removing the power beyond adapter I want to feed a valve for a thumb. The valve will be mounted on the backhoe frame. New valve will not have power beyond.

Can I tee the original return line and the return line from new thumb valve together so I will only have 1 return going to tractor?

Yes, just like ptsg says....you can use a power beyond that way. In fact, I believe that the new valve could also have power beyond and you could daisy-chain valves together that way almost indefinitely while also running the various return lines in parallel or joined. Of course that way you would be losing pressure and efficiency for each new valve in the chain. Be sure to check with the manufacturer of your original valve to see if it requires an insert when using the power beyond port to power another valve. Most valves with a power beyond port DO require that the insert be changed to a PB type when utilizing the port. The insert is specific for each valve & not interchangeable. Many valves come with both (PB & not PB) style inserts when you buy them.

As to your other question about the return line...First of all, you have or maybe just wrote down a misconception about the pressure in the return line. There should not be any high pressure in the return line. A power beyond port should not be used as a return line. Use the return port. In the return line there can be quite a bit of flow, but should be little or no pressure.
I have heard of people having problems when combining two return lines into one. But I believe it has been due to having too small of a flowline diameter. If combining flows, you may need to make the return line larger diameter both before and after the junction. Use good practice, i.e. a "wye" rather than a '"tee".
rScotty