help need with problems with front end loader raising unless back bucket is raised

[goinesp]

I have a 30HP Terraplane tractor . I been having problems with front end loader raising but now I can't get it to up at all unless I work the lift on the back bucket at the same time then it goes up in a hurry. Tractor repair man told me it was probly the Spool valve bad for the loader so I replaced it with no change.