JD 4020 front end loader valve issue

[steve-in-ga]

I've got a John Deere 4020 with a bush hog loader (2847 QT). I had the loader off for a week while I used the tractor to bale hay. Went to put the loader back on today and hooked up the hydraulic lines and I have oil to the input of the
joystick valve which is a walvoil valve but no action when I move the joystick to try and raise the loader boom or curl the bucket boom. Essentially I can't get the loader remounted to the tractor without these functions.

Looking for some troubleshooting advice for the walvoil valve to try and figure out what's going on with it.

 

[Roger in Iowa]

If using the rear outlet pair for power to the loader, switch the hoses or move the SCV lever the other direction and see if it works.

Sounds like you are putting oil in the return to sump line to the valve.

 

[Tx Jim]

Ditto what Roger stated. Be sure you putting pressure oil to "in port" of joystick valve

 

[steve-in-ga]

Thanks but I'm not using a rear outlet. I have it tee'd into the supply side and return side directly. No way to hook it up backwards.

I slide the rubber boot off the joystick and the 2 spool valves are operating as they should when the joystick is moved.

I wonder if it's possible that the relief valve is stuck open and its dumping all the oil back to the tank when I engage the joystick.

 

[wore out]

(quoted from post at 13:07:18 11/06/20) I've got a John Deere 4020 with a bush hog loader (2847 QT). I had the loader off for a week while I used the tractor to bale hay. Went to put the loader back on today and hooked up the hydraulic lines and I have oil to the input of the
joystick valve which is a walvoil valve but no action when I move the joystick to try and raise the loader boom or curl the bucket boom. Essentially I can't get the loader remounted to the tractor without these functions.

Looking for some troubleshooting advice for the walvoil valve to try and figure out what's going on with it.

Sometimes when you recouple hydraulic couplers and there's residual pressure things don't go quite right and one of the balls or poppets doesn't get unseated and oil can't flow through the coupler in one direction.

Likely, that's what you have going on, since it worked before.

Need to confirm the tips are fully plugged in, maybe try again, and if no help it may be necessary to support loader and relieve the pressure in the appropriate hose.

 

[Tx Jim]

Steve
A simple test is remove return oil hose from tractor hyd system. Remove quick coupler end & aim open hose in hyd bucket or tractor hyd oil filler hole. With joystick centered(neutral position) with engine operating no oil should be exiting open hyd return oil hose if hyd control valve relief valve is functioning correctly.

 

[steve-in-ga]

You nailed it. That's what it was.
Thanks for your help.

 

[steve-in-ga]

Turned out to be the coupler not opening
as it should because of residual pressure.
I'll file this away for later use. Thanks
for your help.