350 U One way steering. New test process

[Paul 300 U]

I decided to start another thread here hoping to get new interest on this old issue . Hopefully those that usually chime in will continue to do so! A few of you might recollect that I have a 350 utility with power steering that only turns one way..i fixed the unit once and it worked ok. I then broke a previously welded shaft in the gear box. I replaced the shaft and now steering will not work. I've rebuilt it 2x focusing on getting the adjustments correct.
If you want a recap on how the steering works please read the following in parenthesis ( ). (This system essentially functions by hydraulic pressure pushing a piston backwards or forwards based on hydraulic fluid pushing on either side of the piston. At the end of the piston rod is a race that connects to gears that move the steering left or right. Fluid to the piston is via a valve in the steering column. The steering column runs through the center of the valve which has ports. Fluid moves through the ports (Left, Right, Centered) based on up and down movement of the steering column itself)

I was discussing my efforts with my local mechanic who has tractor experience and some familiarity with this set up. He's stumped as to why the steering is not working. He doesn't believe the inability to turn at all would be caused by a minor adjustment not being correct. For process of elimination purposes he suggested I remove the two steel hydraulic lines that run from the right side of the steering column to the hydraulic cylinder. (The cylinder contains a piston which moves back and forth depending on hydraulic fluid pressure pushing against either side of the piston. The piston is attached to shaft that activates shafts on the steering box to turn the tractor.)

He suggested I attach a hose to each of the 2 fittings on the steering column and verify that fluid comes out of one hose when I turn left and the other hose when I turn right. This should tell me whether the steering valve in the column is working correctly. I did as suggested and indeed fluid comes out of the hoses depending on which way I turn. The fluid basically stops when the steering is centered.
Is appreciate any input as to what if anything you think this experiment really tells me and where I might go from here.

Thanks as always. Paul

 

[Janicholson]

A chip of gear tooth in the gears would lock it up one way, and allow the other. Jim

 

[Paul 300 U]

Thanks Jim. When the front end is raised it works fine. When I put weight on it won't turn. All other hydraulics work great.

I know you have a 350 as well. Is it possible the problem has to do with the piston is in the cylinder?
Thanks Paul

 

[Janicholson]

Thanks Jim. When the front end is raised it works fine. When I put weight on it won't turn. All other hydraulics work great.

I know you have a 350 as well. Is it possible the problem has to do with the piston is in the cylinder?
Thanks Paul

Lift up one side at a time. If it is related to one link and associated arms, or a gear that has a tooth issue it might point in a particular direction. Also using a jack to take weight off both at once in increments, might point to one side or the other. Does it turn back to ~ center from the side it will turn to,? Jim

 

[Paul 300 U]

Thank you Jim. Sounds like a good starting point. I'm that running out of options here. Paul

 

[Janicholson]

Thank you Jim. Sounds like a good starting point. I'm that running out of options here. Paul

I believe a PS unit from a 460U can be made to work easily with slight mods to the mounting. There has been no radical issues with those compared to 350U. I have not done that substitution. Jim