John Deere 820 3 pt. won't raise

[deere820]

I have a 1969 JD 3 cylinder diesel, built in Germany. I have rebuilt the 3 pt. hydraulics and rockshaft. I didn't change any of the settings when I did the rebuild. I can't get the arms to fully raise up. They lift about 1/3rd of the way up and stop. I have connected a gauge to the port ahead of the pilot tube and only get a brief shot of pressure up to about 500 psi and then it drops back to zero. Any help would be appreciated.

Thanks,
Charles

:confused3:

 

[mdross1]

First thought would be fluid level,on the 2 cylinder tractors the two adjustments control raise and lower speed.Of course there is a bypass the hydraulics has to be deadheaded to get that reading.

 

[Tx Jim]

Where/what is the object you are calling a pilot tube? Where is L/D lever under seat setting(L-LD-D)? Lever should be setting in "D". Did you get the cam(parts key #9) back in correct place in RS valve control linkage? Also is spring(parts key #10) intact and attached correctly? It's possible that the L/D control mechanism needs to be adjusted following adjustments outlined in JD tech manual.