... my older Bomar port light frames are anodized aluminum, the dogs are held in place by SS allen cap socket screws, these thread into a boss on the port frame. The screw fastens the dog in place and adjusts it's depth, there is also a SS 7/16" nut, between the dog and the frame, that the allen screw goes through and this locks it's adjusted position in place against the port frame. Some of the nuts and / or screws are corroded and frozen on or in the frame, salt water has probably wicked in over the years, I should have been doing a better job of protecting & lubricating the dissimilar metals with Duralac, Tef-Gel, whatever. Making things worse, the outside of some of my ports have also leaked over the years due to failed bedding at the coachroof, so some salt water has gotten behind the frame and possibly dripped onto the ends of the screws where they are threaded into the frames. I think I've fixed this problem, I gouged out the old bedding with a sharpened church key and re-caulked, some day there will be new New Found Metals port lights.

I haven't yet spent much time on the half dozen or so frozen screws. Note from the picture, my lights are angled outboard at the bottom so any penetrating liquid will drip off the screw, and not into the threads. I did try a day or so of spraying with WD40, which didn't work, then I tried PB Blaster, and that didn't work. If I bust a screw, I'm going to be screwed. Next, I think I will try ... saturating a rag or gauze with Kroil and taping it the screw overnight, hoping the penetrant will wick into the threads and break the bond. Whack them with a ball-peen. If that doesn't work, heating the allen screw with the point of a soldering gun, or even a small torch, but I have to be careful not to melt the dog. Try turning the screw with a large set of Vise-Grips, if I can get a grip on the screw without damaging the dog.

Anyone got other ideas ?

thanks, cheers, John