Hi!
Most of my bungs were not great. And the screws were really rusty. The PO had but random screws in, i had to use larger thread screws to fit well.
I used a very cheap method to sort my westy roof - wine making demijohn bungs. Cheap to buy, hole in the middle for a screw. And you can cut down to size to get the right height,with a couple of rubbers, and for the rear corners. At the very front middle and sides, i think i used some rubber washers of maybe, 2 or 3mm so it had some give, as i didn't want to be screwing fiberglass straight onto the metal roof.
Used some bathroom sealant (which has set hard, instead of silicone which will flake off) underneath bung and through the screw hole to seal it to the roof. As when i first did it, rain water dripped through the screw thread and dribbled inside the van - causing wet pillows at V fest last year :roll:
Once i sealed it, it was fine. They have a solid feel to them, and seem ideal, so go and find a wine making shop, and ask for some red demijohn bungs. Or, go down the tip, they usually have demijohns, but most people keep the rubbers. I got some of mine from Freecycle, the rest i bought, the remainder i sold for quids on here last year, along with my OG ones.
They have been on a year, fine, no problems.
Sorted.
Alistair