Yeah I wouldn't know about imperials, never owned one. I just know you make them sound as good as the new yorkers and I take mine for granted. If I found an imperial, who knows what I'd think,lol. Those were good years for chrysler.
It sucks for the shocks you can't buy them new anymore. I got the 91 used nearly 2 years ago and the shock were acting up,so I call around, and came across the "kyb gas adjust" shocks advanced auto sold me. I drove with them on for awhile and they let my rear end sag and bang around all the time, so I checked a local pull a part yard and found the original shocks only thing is of course used is never guaranteed, but these parts are so old, you're lucky if you find them used. The ones I got from the pull a part came with a 30 day warranty for a dollar more, and I stuck them on. They operate like they are supposed to and keep my rear levelled and not banging around, but they are leaky. The compressor kicks on every minute or so for a few seconds, so I'm thinking I may use the material that's for brake hose lining and replace the leaky hoses on the shocks and maybe that will make it air tight and not so leaky.
If you let them constantly leak they'll soon go bad and be useless, so it's good to try and fix the leak if you can. I always thought the hoses could never be pulled from the shocks and replaced. The first set I bought I cut the hoses and the was going all over the place to find connectors which did no help, so I took the shocks back and got a different pair. I found out if you just lay them on the ground or something and take a heavy duty plier, just something with a good grip and pull hard enough, the hoses will pop off, then there are the clamps on the hoses, which if you lose the clamps,the whole thing is history, because it pinches the hoses in place inside the air shocks,so you wanna make sure those little hose clamps or whatever you call them, stay on the hoses or if you replace the hoses and have to pull them off, put a bottle or something to secure it,at the end of the hose, so when the piece flies off , it lands in the bottle and doesn't get lost.
To replace the hose, get brake hose material from the auto store, run those clamps maybe 1/4 inch from the end of the hoses and put them back in the way they came out and you should have have air tight shocks. It's a matter of measuring the hose length of the ones already on the shocks and cutting the brake hose material the exact same length. I haven't tried it yet, but I will be. The auto store says the brake hose material would be strong enough to hold the air pressure, like the hoses on the shocks do, so I'm gonna give it a try sometime. It sounds like it will work. I know the steps to service them will work, it's a matter of finding the strong enough air hose, you wanna be sure to look for.
Those shocks are sacred and if you have them, you wanna maintain them as much as possible or they'll be history and you may not ever come across them again. They are a neat invention that chrysler put an end to. I wish they still made them, because they were worth not having to manually level out the vehicle. That is a headache too. I had the auto store even sell me the manual shocks you have to have a compressor to air up and let the air out yourself when not in use. That's a pain, and no one is gonna wanna do that all the time to go places. It's like every time you add a person or any weight you have to air it, then let it down. They say you can't just leave air in it or it won't be a good ride that way. I've learned if you have the original shocks, hang on to them and maintain them the best you can. I did my shocks 5-6 times trying the get replacements like the original and it was a nightmare the whole thing was. If you have a leaky system try the steps mentioned to restore the thing while it's still working and you may have yourself a set of refurbished shocks, you fixed yourself. I take mine for granted.