I have a 1950 8n. The 3pt was not going up unless I put air pressure in the hydraulic check hole. So I decided to rebuild the hydraulics I tore it all down and put it back together with all new parts gaskets pressure relief etc. It went very well right up to testing my work.
The arms no longer lift at all. There is no fluid coming up through the tube that is feeding the hydraulic ram. Is there another reason? Bad valve? Any tricks?