Weatherstripping sealant

[pentode]

A bit of a bodywork saga, but I'll keep it brief. I had what I thought was a paint chip rust bubble situation right at the top of the topmost door seal. Turns out, someone had mounted something to the roof with 4 holes, 2 on each side, just below or right at the edge of that seal, then when they removed it, they just filled the holes with silicone.

Anyway, when I peeled off that piece of weatherstripping (which grabs the seam between the roof and the cab body) I found that that seam has been marinating in salt water for who knows how long... a serious amount of rust.

Upon removing that weatherstripping from both sides, I could see that there was _some_ sealant right at the top lip, but it wasn't really doing anything in my case, either because it failed over 20 years, or more likely, when they peeled off the weatherstripping to drill those holes, they basically broke the seal and it never sealed properly after than. And that led to both sides being permanently wet.

So here's my question. It looks like the very top edge of that piece of rubber has a flat spot that's meant to be sealed to the body of the truck to prevent water ingress. Is this the case? Because if not, I can't see how water doesn't just creep in there and soak that seam around the roof panel.

Assuming that's the way it's supposed to be, anyone know what the proper sealant for that is or have any good suggestions for a substitute? I'll try to attach a couple pics soon in case I did a poor job explaining. It's that top piece there, you can see the holes right where the top edge of the rubber sits.

 

[franklin2]

From what I have seen, the factory spot welds the roof at that pinch weld/gutter, and then puts some sort of hard seam sealer in that area that can be painted. It can chip off after years, and cause leaks. I have never seen them rely on a rubber seal to seal the spot welded areas.

Maybe they did on the later vehicles. My wife's honda is put together on either side above the doors, and it has a rubber strip up there. with no rain gutters Still hard to believe that is the only thing keeping the water out though.

 

[pentode]

It's hard to know what was coating those welds as most of it has disintegrated - but it looks like just paint for the most part. I was trying to think of something to fill in that groove with that wouldn't make it completely unserviceable in the future, fluid film or something along those lines. I hit it with the wire wheel, then some rust converter, then a light coat of paint, but whatever I did today is just temporary. I need to go back in there and try to slow down the rust and, ideally, keep so much water from getting in there. I'm thinking I might need to run a small bead of ultra black along the very top edge, then find a way to get it to sit nice and flush while it cures.