KZ1000 air shock rebuild

I have a 1980 KZ1000E2. About a year ago, I put some air shocks on the rear. They were manufactured by Kawaskai, and came off of an early '80s model 1000.

I ride on a lot of rough road and love these things-- I can ride over washboard and barely feel it, it is great. However, my shocks, being pretty old, have always leaked a little oil out of the seals. Over time it has gotten worse. I figure there's only so much oil in there, so I better start thinking about how to replace the oil and seals.

I have three sets of these air shocks-- all manufactured by Kawasaki. Unfortunately, they all leak oil at the seals, as old suspension parts will do.

I've looked around online but haven't been able to find any replacement seals for these things. It seems the thing to do with these shocks was to take them in and have Kawasaki rebuild them, or just replace them. But, now that these parts are several decades old, it doesn't seem like that's something Kawasaki does anymore. They are still solid parts-- aside from old rubber seals. They've got to be rebuildable somehow.

Looking at it, it seems like that seal in there is basically just a fork seal. And I imagine that's maybe (?) just fork oil in there.

But, if a fork seal will work, which fork seal will work? If it's not a fork seal, what kind of seal is it? And, how would disassembly and reassembly work? What kind of oil is used, and where does it go? These are the kind of questions I've been chewing on.

Anyone have any experience with rebuilding these? If so, please let me know-- I really don't want to give up my air shocks. And, these things are good parts, it would be a shame to junk them just because of bad seals.

Thanks-- long live KZ.