My 1984 had leaks around the AC unit and other place in the middle of the RV.
I purchase a new AC gasket, a piece of 1 1/2 square stock alum. the exact lenght of the RV left to right outside, a 24 inch piece of 1 1/2 flat stock alum. 4 3inch by 5/8 bolts with lock nuts, and 6 large flat washers.
Removed the AC unit. With a floor jack and blocking raise the roof from in side till flat. Place the square stock on top of the roof just ahead of were the AC unit is mounted with cover on. Drill 4 5/8 holes, 2 at six inches in from end and 2 ten inchs out from center.
Scott M
July 2008