All of our port lights were leaking and looked pretty gross. We have 6 port lights that open that we rebedded first, here's a link to that post. This post goes over how we rebedded our 4 non-opening port lights. It was a little more labor intensive and required some redesigning to make sure they wouldn't leak in the future.
You can see how much gunk was built up on these. No wonder they were leaking! I used a scraper and a flat head screw driver to get it all off. All of the port lights needed to be scraped, cleaned up, and restored first, here's a link to a post I already wrote about that.
After we got them all cleaned up, we had to come up with a game plan on how to go about reinstalling them. The original design was stainless bolts threaded into the aluminum frame. After 46 years, corrosion had eaten almost all the threads. We decided to drill out the frame and use through bolts instead. Our headliner is pretty warped and has a lot of unevenness so the through bolt allowed us to tighten more or less where needed and achieve a better seal.
This is the outer ring of the frame. The one on the left is what is looked like before we drilled through.
Prepping the lexan to be bedded into the outer frame. We taped on both sides so we wouldn't have a huge mess to clean up and to keep things nice and tidy.
We used Sikaflex -295i UV because that's what is recommend to bond lexan to aluminum. First you MUST apply the Aktivator otherwise you may have improper bonding and could end up with leaks again. Then we filled the inside edge of the frame and lightly pressed the lexan into it. We applied light pressure so we didn't squeeze out all the Sikaflex.
We left them to dry and cure for about a week just to be sure - and we had a ton of other projects going on.
Ok, so now we are ready to reinstall the port lights. Again, we used butly tape to bed the frame to the coach roof. This is the good butly that we mentioned in the opening port light post. It is easy to work with and so far has produced great results!
So this is the outer frame all ready to go. We ran the butyl around the outer edge of the outside frame and then pressed the frame into place. For the inner frame, we just applied Lifeseal around the bolt holes to prevent leaking through the fasteners, and then pressed it on.
Here's all the new hardware: stainless bolts & cap nuts with nylon washers between to prevent corrosion.
Here's the port light installed. After letting things settle and cure for a few days we used a razor blade to trim off any excess goop and then removed the tape.
A view from inside. All done! Everything worked great. Our one regret is that we didn't just go ahead and replace the old lexan. It's scratched and starting to develop crazing so we should of ditched it. We just didn't realize how good the frames would turn out so we didn't worry about it! That'll be a project down the road, but for now, all the port lights are clean and dry!