Rear Air Suspension question
you'll have to take it to a reputable shop to have the lines and fittings inspected for leaks
worst case scenario is that you're into air spring replacement. a common thing with these trucks.
just did 4 all around with my uncle's '11 GL Bluetec.
my '08 320 CDI had 3 out of 4 replaced before i purchased it, phew...
you can get good deal from aftermarket manufacturers too
my local euro parts supplier had them in stock






