See my response in the thread at the bottom here if you are talking about the firm rubbery gasket material.
You can repair weatherstripping sections with good quality generic door/trunk auto weatherstripping from the parts stores. It is closed-cell firm stuff in various cross section shapes (not the squishy open-cell stuff). I believe there are still a few companies that make quality stuff, but also a lot of China junk on Amazon, so the best bet is to go to a good local auto parts store, or better yet an auto-body repair supply shop, which will likely have it, and may even have rolls of the stuff available cut to length.
This is not anything new, people have been repairing car weatherstripping like this for decades. Up to a few years ago, NAPA and Carquest in the US had a big paper catalog where you could select from various cross-section shapes and sizes of weatherstripping (in different lengths), but the selection is limited now, to mostly rectangular shapes and a few others, but you can make it work. It won't look pretty when you open the door or trunk, but it will seal out rain if done carefully.
It does take some patient careful cutting, and then glueing with the special Permatex or 3M weatherstrip adhesive to make sure it seals the to the metal and remaining good weatherstripping. I have repaired my door weatherstripping this way a few tiems, since finding junkyard donor cars is difficult these days and the remaining new-old-stock stuff on ebay in the US is overpriced. Another possibility though is using weatherstripping with a similar cross-section from any other junkjard donor car and glueing in a patch section. Using stuff like RTV, Shoe Goo, or similar to make repairs to weatherstripping doesn't work very well since it doesn't seem to last; your best bet is to fit the repair sections and glue them to the metal and intact weatherstripping with the special weatherstrip adhesive.
As far as windshield and rear glass rubber seals, a good specialty auto glass shop may be able to improvise with the various seals they have available (comes on rolls also). After all, they can still get glass for many older cars and have to seal it. The guys that do mobile glass repair obviously won't have much of a selection, you have to take the car to a shop.
The hardest things to repair are the seals and trim below the roll down side glass, though I am improvising the rubber trim pieces on those with some cut and shaped body side moulding (tedious with Dremel). The part that "wipes" on the glass as it goes up and down might be able to be improvised somehow from a different donor car, but thankfully those are still good on my car.
Hi My trunk leaks when we get a hard rain - the rubber gasket seal has a few little chunks out of it at the bottom near the latch area. Are there any known issues? Any hoses from the sunroof (which never is opened) or any other things to look at? Can I get a new gasket for the trunk or is there...
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