Hey all - I’ve been slowly losing my mind regarding this matter.

1971 ford f250 with bendix power assist
new power steering control valve
new PS fluid, bled

the front tires shudder pretty violently when rotating the tires at stop/slow speeds.

in addition to that the return line (picture) vibrates and shakes anytime I rotate the steering wheel.

anybody know what might be causing this?

 

As pointed out in the thread you started on the 15th all that stuff has been swapped into your truck. There was no PS available in 4wd in 71. YOU have to figure out what all that stuff came from and if it was installed correctly. Then possibly have the parts rebuilt by someone like Red Head or Bluetop.
Welcome to Blue Top Steering Gears - A Quality Product with a Competitive Price! (3dcartstores.com)
Red-Head Steering Gears (redheadsteeringgears.com)

 

Take all that stuff and throw it in the garbage! Change over to a 1978/79 style power steering box. So much easier in my opinion.

 

Here is another thread to read thru. Get in the 73-79 forum because no 67-72 4X4 came with power steering. You are going to spend considerable money whether you swap to 78-79 or have what you have rebuilt. Your cheapest way out is to put it back stock and just have manual steering.
1976 F250 to 78/79 steering - advice - Ford Truck Enthusiasts Forums (ford-trucks.com)

 

Is it a shudder, like a vibration? Or is it more of an oscillation of the tires when the vehicle is rolling?
And does it do it in all positions, or just while turning?
Just wondering if frozen up axle joints could be compounding a problem that you have with the power steering.
Generally I agree with the others that the steering system you have is a problem waiting to happen. But yours looks reasonably new and leak free, other than all the hoses looking pretty ragged.
The lines up to the cooler look pretty new, but everything down at the control valve except for one look like they’ve been there for a long time.

How extensive is your other discussion?
Usually better to continue one, rather than start over.

good luck