[77newell]

My 77 coach was developing surface rust spots on the framing and really rusting the rear wheel wells. Living in Michigan and leaving the area or arriving back in winter will expose those parts to salt. Washing is critical first line defense and I didn't do enough of that and hence my rust issues. Be absolutely sure that the separation film between the steel framing the aluminum skin is present or you will be amazed at how fast pinholes appear in the aluminum following exposure to salt.

I have replaced the deteriorated poly separating sheet with heavier shrink wrap film, wire brushed rusty spots, treated those spots with rust converter and topped it off with an oily undercoating. I don't have a lot of miles on it since so I can't verify durability. In my earlier life I would just spray a mixture of used engine oil and diesel fuel on rusty spots and that seemed to work quite well. It was cheap, penetrated into nooks and crannies, and was messy to install.

I've also put a rubber roof flashing on some more effected spots in the rear wheel wells. It is self-adhesive but it didn't stick very well so I used rubberized roofing tar as glue - so far so good as it is still in place.