The Boge unit is effectively a self pressurising air spring , with a built in limiter . It was fitted to range rovers , and mostly 110 csw .
It allows a softer spring to be fitted at rear for unloaded/partload running , and then when fully loaded the boge unit stiffens the rear . If you just remove it the rear end will sag when heavily loaded.
It was removed by land-rover as a cost saving measure, going for a cheaper variable rate spring , it is noticeable when they did it as 110 started driving with the tail end up in the air . The range rover had migrated to air suspension. Dont try dismantling .
IIRC there was a guy looking at remanufacturing , on one of the Landy forums . When working they are very effective , when not they dont do anything other than use up part of your gross weight.
If the locating ball joint is u/s then it can be replaced , and the modification springs can take the place of the Boge unit . HTSH