I'm trying to rebuild an old rear shock absorber of my car (LR041110 was installed recently). This part is stil air tight so I'm considering buying a new shock absorver only.

Anyone tips and a guide how-to succesfully replace this. I got stuck after removing the upper shock absorber nut and lower rubber cover, and rivit. Separating the shock absorber from the airsuspension seems to be "impossible".
Don't want to damage something so any help is welcome