In your first post, you said that the end of the pittman arm to the steering valve was where the slop is.
Is that still the area that you think is the problem?
The pittman arm connects to the steering valve by a short tapered shaft that comes off the steering valve. That shaft is pressed into the pittman arm and held by a castellated nut with a cotter pin in the shaft.
The valve itself has about 1/2" travel side to side as it slides back and forth opening and closing the valve to control the flow of steering fluid to the cylinder.
As you were bleeding the cylinder, the steering wheel only needs to be turned about 1" in either direction for the cylinder to start moving. You should visually verify that. One thing that might help is to jack the front wheels off the ground so there is no load on the steering. Then you can see where things are moving or not when they should.
Since it was good before you replaced the steering assist cylinder, that's where I would assume the problem is. But you might have some slop in the steering box before it connects to the steering valve, which would account for several inches of steering wheel movment before the valve is actuated.
With the wheels centered and the engine off, try to push on the wheels as if you were turning a corner. There should be no movement in all of the steering linkages(I.E. loose linkages) and the steering wheel should tilt in the direction you are pushing. But it won't move much because of the hydraulic pressure in the cylinder. If it does, there's air in it or the piston seals are bad.(yes, I know it's new, but sometimes a new part is bad.)
Also check for movement in the rod end bushings to the frame bracket. Old bushings can cause a whole lot of slop in the steering. And check to make sure the bracket is securely bolted to the frame.
As a point of interest, when I got my 82 the steering cylinder had just been replaced at a dealership. Not only were the bushings shot, but the bracket bolts were loose too. It was a crazy, scary, wild ride until I put new bushings in and found the loose bolts(4) on it.
Check it out and let us know what you find.