Easy marker light maintenance
I spent the first year with my '65 airstream wondering how to keep water out of my marker lights. I knew it wasn't good for the electrical connections and I suspected was a potential rain water leak into the wall.
So about a year ago I took action and have very good results to report.
I bought a sheet of "kool Foam" from my local craft and hobby shop. Its basically 1/16 thick dense foam rubber sheet. I called the manufacturer and confirmed that it is water, weather, oil, and ozone resistant. It comes in lots of colors but I chose black. I cut a strip a about 1/2 inch wide and 8 1/2 long with scissors. I took off a marker light lens and wrapped the strip around and trimmed it to overlap about an inch forming a loop. Then I put the lens down, increased the overlap about 1/8 inch more, and glued the overlap together (under the entire overlap) with Loctite gel contact cement (from the hardware store). Clamp the joint together over night and repeat for however many marker lights you have.
Next you install the lens on the marker light and slip the band tightly in place. It stays put even during travel. It doesn't degrade noticably. Best of all, it covers my old, yellowed marker light base and the joint between the base and the lens. So the waterfall of rain water can't get into the light.
The other things to do are to seal the marker light base to the skin. I used Parbond. Take all the light bulbs out one by one, clean the bulb end and the brass socket (I used pecil eraser), grease the socket with silicone lube, and reinsert the bulb.
If you have to push on your marker lights to make them light up, they probably have a bad ground to the aluminum skin. Mine use an (original) aluminum pop rivet through the brass contact, through the plastic base, and into the aluminum skin. Aluminum and brass is not a reliable electrical connection because it corrodes. I found that a squirt or two of tv tuner and switch lube (from radio shack I guess) directed at the rivet head / brass contact made all the lights work. Its been months now and they work fine. So I am putting off drilling the rivet and putting in a new one with Aluminum / copper paste in between.
Anyway, I hope this helps. By the way, I used the "kool foam" to make home made gaskets in places too. Use Vulkem on both faces for a good seal.
Bill aka Cosmos