On my 1987 scamp
13 resealing the rear window, scamp
greatly overcut the hole and made it easier for there to be a leak. I had to use a double layer of Butyl tape in the corners to get good squeeze out. I also had to make sure someone was pushing the window up while tightening the clamp ring in place. The factory installation with the foam tape seal will not hold the window in place once you get the screws and trim ring out so have some help. Before taking the window out get some masking tape and tape the fiberglass close to the window. Then after you cut off the squeezed out Buytl removing the tape gives you a clean line. Dont try to remove the excess buytl when its hot out or in the sun or all you get is gum on the shoe syndrome. Cut it loose and remove while its cold in the morning.
has Hehr slider windows
and their foam seal they used was a joke for seal on such a nice window. I also had issue with some of the screws rusting in place after 25 years and making them hard to remove partially stripping the heads, screwing those back in would make removing them later impossible. I recomend going to the local RV parts supplier and getting some extra screws. They usually have them out back in their repair shop. Take an old screw with you so they know what your looking for. They are cheap insurance compaired to the frustration they can cause you. Resealing the newer windows
are a piece of cake you just need to have 2 people if the windows
haven't been resealed with putty before.