1980-1990 GM B-Body doesn't seem to get a lot of aftermarket love.. My rear headliner is sagging, and I get some moisture inside the rear of my car, and I think it is due to the roof rails leaking. Looking at the gaskets, many are missing chunks and all are brittle. Has anyone found replacements? I'm striking out.
Are you talking about door or tailgate seals? If door seals they are the same as a sedan and are available. Tailgate seals are more problimatic
If you can't find OE seals for the roof rack, go to any RV service/parts place and buy a sealing foam that you cut pieces and place under each foot, then run the screws back in to make the seal.
No, the rails on the roof; AKA the luggage rack and rear spoiler. I don't think I can use the Sedan version.
"Roof rails" is the term for the rubber seal at the tops of the doors. It appears that the OP is talking about the roof mounted luggage rack. The factory installation of the luggage rack involved drilling holes in the roof and using self-sealing nutserts that squeeze the sheet metal and seal as you tighten the fasteners. The skid rails use sheet metal screws with a plastic gasket under the rail. The gasket deteriorates and leaks ensue. This is why I hate roof racks.