My backhoe only steers good to the right. Can do it with one finger. But turning the other way is almost impossible unless moving a little and still it is definately no power assist. Any suggestions other than buying a power steering valve? Bought it that way.
My Ford 5550 had the same kind of failure. Turns out the snap ring that centers the spool valve broke and let the valve float around, so I couldn't steer it. If you don't have the service manual, you'd better get one. All these tractors use different methods of doing the same thing. You need the manual to figure out how yours works. Once you have the exploded view of the steering gear it'll be clear of what you need to fix. Or failing that, when you take it apart and find the broken/worn parts. Maybe somebody with the same tractor will chime in with his fix, that's about the only way you're going to figure it out without the manual. BTDT.