Need Steering Box Help !

[78longbed]

I believe that my son's sreering box is in need of rebuild or replacement.
He has a 1979 F250 4x4. with a 400. the steering gets tight on and off with no return from the power assist. We have replaced the box with a spare. it was the same for a while, but loosened up and was fine until last night, with the same symptoms. We figured that two boxes wouldn't have the same problem , but maybe they do. We replaced the pump with a new one today and have the same issues, tight intermittenly with no return when turning. Do you guys think that it is a steering box issue? Can some one recommend a good rebuilder or a reputable and reasonable place to buy one? Also I have not touched the ajustment screw on either steering box.

Thanks,
Jeff

[mark a.]

Did you check the front axle u joints ? Sounds like one or both might be froze up.

[mudslingin'78]

Or even the steering damper, if equipped, can have that effect as well. It could be worn and binding.

[78longbed]

Good suggestions, I don't think that I have a steering damper, the steering stablizer is new. Is there an easy way to check the front u joints without pulling the axle's?

[Ford_Six]

Reach your finger in there and see if you can jiggle them, or if there is a powdery rust dust around there. It could also be ball joints, or it could be dirt in the power steering system that keeps clogging the valve in the box.

[mark a.]

Turn the wheel all the way either way and reach in to the u joint and see if the axle will turn free.

[78longbed]

axle and U joints turn free, the U joints are dry but not frozen up. Also all ball joints are new.
Is it possible to disconnect the lines from the steering box and blow it out with air while turning the wheels to clean out the box? I have power steering fluid in the pump instead of ATF.