Changing a rear bag is very simple. Jack up the offending side and remove the wheel (by jacking up the chassis). Remove the air line. Remove the "R" clips top and bottom (hence the coat hanger tool - make one end into a hook), wiggle the old one out and the new one in!
The fronts are a bit more involved. It helps to remove the inner guard but it can be done with the inner guard in place. Remove the air line, remove the 2 small clips on the top of the spring, jack the chassis up, undo the small bolt that holds the bottom "R" clip (13mm from memory), remove the said clip, out with the old and in with the new!
The hardest part is getting the air lines off and back on again! I replaced one in the bush in less than 20mins with only my teeth and a nail file (ok - I kid, I used a screwdriver and a bottle jack)!!
Easy done

