johnrolo, i done my back left in an hour, simple job, lower car 2 access level, leave t boot or a door open with t engine off. jack axle remove wheel, now lower axle on to a stand, now jack t chassis slightly, remove all securing pins and t air line that can be t tricky part, clean off all t dirt first , cover t pipe with cling film now jack t chassis higher and pop out t bag, refit is t reverse, last thing is restart t engine, get her up and check for leaks with soapy water, this worked for me 3 times, 1 bag was done when i got her a year ago this wk .pat