I did some reading last night on the hydro pneumatic strut. It appears they are not adjustable. But, apparently, under the rubber boot there are two filler plugs. This is the term used by Haynes. Possibly the fluid can be replenished, if need be, but I'm not sure. The nut you spoke of on the one side is a self tightning lock nut. This just is an anchor for that side. I did check my camber and it is off. The top of the rear tires lean in slightly. I confirmed this by putting a level against the tire. I jacked up the rear, off the ground then put it back down again. This fixed the problem till I drove the car this morning lol.
I think the best fix for these is just to replace with a spring. From the factory some of these cars had the spring, others had the hydropneumatic strut. The only difference is a slightly smoother ride with the strut. But the spring is going to be a lot cheaper to replace.

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Just a head bangin' hell raisin' hillbilly man