The normal suspicion and such related to what I term "the top-side adjustment", which is the highly visible nut/stud adjustment on the top of the steering gear. The "unknown about" adjustment is on the INPUT side of the gear. Even when adjusted when the gear is first produced, this "input adjustment" has a spec just like other areas of the gearbox. As you or an assistant lightly turns the steering wheel side to side, engine off, usually, but not necessary. The steering column (at the gear) will visibly move in and out, yet the innarrds of the gear do not move, nor do the front wheels. If you look, there is a huge spanner nut around the input side of the gear, which is where the adjustment is made. Takes a special took, I believe?
You can adjust the top-side adjustment until there is no natural caster-related return of the steering wheel from a turn, and STILL have the "play" due to the wear at the input side adjustment needing to be addressed! Same with getting the rag joint replaced and play there minimized!
From my experiences, the adjustment of the top-side adjustment needs to be done in very small increments. Like 1/8th turn at a time. Back-off the adjusting nut and with a long screwdriver, adjust the stud inward slightly and then lock it down with the lock nut. This adjustment can adjust-out SOME of the wear between the two internal steering gears. 1/8 turn of the stud each time until the steering shows the slightest sign of not automatically returning from a turn to its center position, then remove 1/8th turn of the stud and leave things there.
In times past, I acquired a '68 Buick LeSabre. The steering felt uncharacteristically over-boosted and would not automatically return from a corner. I did the top-side adjustment and when done, it felt normal-GM rather than over-boosted. I never did mess with the input-side adjustment (GM terms that "adjuster plug" adjustment. There is also a similarly-name lip seal there, too.)
The "rag joint" and "coupler" can also have wear/deterioration issues, each. So in the case of these items, you can work backward, up the chain (so to speak) to diagnose them. No adjustments, just replacement by COMPETENT technicians.
To me, the KEY thing is to not be "ham fisted" in the approach, but to use finesse and pay attention to what "the equipment" is telling you (or the tech) so that things are done "just to the edge" of being too much.
Other options are to replace the gearbox with a reman unit from Steer & Gear or Firm-Feel. I'm not sure which might be the better one, but others in here do. Also the Borgeson upgrade to a later-model OEM Jeep gear box, too. If you are chasing that "late model feel", this last option might be the best, but might also be a bit out of character for the car?
OF course, you'll also want to inspect the steering linkage for "no play" at the joints. The idler arm condition is important here, too! BUT it can also make you aware of how unique some of the Imperial front end pieces are from normal C-body Chryslers, in some cases! You might check out the website of the "Online Imperial Club" for information in this area.
Sorry for the length. Take care.
CBODY67
