deere 2520 with Bradco Trencher Hookup Question

[ac2520]

Hi Folks,
I have a John Deere 2520 that I have installed a power beyond in order to use my Bradco trencher. The trencher has a Metro valve that is behaving as a closed center valve when I really think I need an open center valve. I was hoping that with a few details and pictures, I can get your help to confirm.

So here are some details:
- Tractor with the power beyond output port looped to PB input port operates normally. 3 pt hitch raises and lowers fine and all other hydraulics work fine
- Trencher boom raises and lowers fine when connected to the PB, but the tractor 3pt hitch quits operating when the trencher is connected. Does not raise or lower. I can't say for certain if the fel hydraulics are affected. I forgot to check and am 400 miles away now.

My connections are as follows:
tractor PB OUT ----->trencher valve IN
tractor PB IN ------>trencher valve OUT
trencher valve port A ----->trencher cylinder
trencher valve port B ----->trencher cylinder
trencher valve port PB is capped

Below are picture of the setup. One picture is of the valve plug that I believe is used to convert from open to closed and vise-versa. The spring make me suspect an Open Center setup because when I see Closed Center plugs online there is no spring or insert. Any and all help is appreciated. My hydraulics experience and knowledge is close to zero.
Thanks

 

[Tx Jim]

Do you have 2520 rowcrop or CUT tractor?

 

[ac2520]

Sorry I should have been more clear. The tractor is a 2520 CUT. Thanks

 

[kennyd]

I am gonna assume a 2520 CUT. That machine has Open Center hydraulics. If you plumb in a CC valve then all flow will stop and the PRV will open, laboring the engine and cause the fluid to overheat.
If your trencher valve has a PB adapter in it, and it looks like it does in your second picture (the center port on the bottom says PB right?)-then you cannot plug that port.
The plug with the spring behind it looks to me like a PRV (pressure relief valve), not a CC/OC converter plug.

 

[ac2520]

Yes this is a 2520 CUT. The port on the trencher valve is a PB port. Since I only have 2 ports coming in and out of the tractor (PB IN & PB OUT), I'm not sure where to connect the PB port from the trencher valve. I think what I need is an open center valve for the trencher. Does anyone know how to confirm I have a closed center versus open center valve? Can these be converted? Thanks.

 

[kennyd]

By definition, since it has a PB port then is an OC valve-and that is what you need (your tractor is OC). To convert to an OC valve without PB (just IN and OUT ports) you will need parts from the valve manufacture-not likely to easily find those.

To make this work easily, you can plumb the OUT port (of trencher valve) into the tranny fill port temporarily, or another port on the side of the transmission case-but that needs a special BSPP style adapter fitting on your 2520.

->The PB OUT from the tractor goes to the IN of the new valve.
->The PB port of the new valve goes to the PB IN on the tractor (this continues the flow to the 3PH and then finally to the sump).
->The OUT port on the new valve must go to a sump-you cannot block this flow as it return the "waste oil" from the cylinders to the sump.

 

[ac2520]

Kenny, thanks for the suggested connections. I'll try to see if I can find a port on the transmission to connect the trencher valve out. I may go to the dealer to look since I won't be down to my property for another couple of weeks. This way I can order the supplies and have them ready to go. Thank again

 

[kennyd]

Check your PM's...

 

[J_J]

I don't think you have a complete path for everything to work correctly.

I believe the plug with spring and poppet is a load check valve.

If you are going to use PB, then you need an adapter to flow fluid to the next valve.

The way you have it connected, the out from the trencher will go to tank.

All PB's should go to the next valve supplying pump fluid.

If your trencher valve is the last valve in the flow path, then you can plug the PB port without adapter. That causes all flow to exit the OUT port.

If you plug the PB port with adapter, you have made the valve CC.

 

[ac2520]

J_J, thanks for your response. I thought that the trencher valve would have been the last valve in the path, but apparently not. It seems that the 3pt hitch comes after the PB output. Since my valve has the PB port, would that be used in place of the adaptor? If not, then I'm not sure what type of adaptor you mean. Seems the key item is to have my output port from the trencher go to the tank as you and Kennyd have mentioned. So it appears that using my trencher valve PB port to feed back to the tractor's PB, it essentially is behaving like the loopback hose that I have connecting the PB ports when nothing is connected to the tractor. Thanks again