Quote Originally Posted by Crasher View Post
Technically speaking the typical damage in this area is only covered by the three year paint warranty, the corrosion warranty only covers perforation rusting from the inside out and this is more inside, then under and up the other side. Why some plonker specified an absorbent foam for this task is anyone’s guess, total stupidity probably caused by a penny pinching accountant and a young engineer who did not understand rust, only NVH.
Outside influence by a rubbish design hey. Stopped the vibrations a treat but friction, grit and salt with water as the sponge pushes the plastic sharp inner wing against a lightly protected inner side of wing is never going to work.

On my second Mk5 Golf before it started I whipped the sponges out, treated them with primer and pained in inner wing with some Epoxy Mastic. Far better than what VW did on my first Golf. Then adjust inner wing so it doesn't rub.

As for inside that often means from under the paint outwards, not inside of the wing to outside either through or down and around.