some models do not have the center lock fitted someone will be able too help you there I think around 2002 models, I have the air bags fitted to mine and I have owned it for nearly 12 years.
As for the air bags keep them It is handy for keeping it level no matter the load in the rear, the only modification have done is fitted one way flow
restrictors, this was because going down steep banks the back end would sit higher which would make the computer deflate the air bags.
Which when going back up any banks with the back end lower a bit harder, fitting the restrictors fixed this but they allow normal air flow rates when adding more air to the suspension but slow the air flow rate when deflating the bags.
disco seriesII mods so far:-bullbar,hyd winch,
detriot locker,lsd front,C.D.L kit,chipped and bigger intercooler,2" lift,rock sliders, lsd in transfer case, modified auto trans.
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