When I had my 1994 'vert, the rear window began breaking loose from the seal at the lower driver's side corner and up one side about 4 inches. I took it to a fella that replaces tops and interiors, and he suggested I try some Superglue on it before we replaced the top. According to what he told me, that was my only two options. He said that once they let go, they couldn't be resealed and top replacement was the only route.
I went to the drug store and bought a couple of tubes, and he helped me with it. The trick was putting pressure on both sides of the glass and top (interior and exterior) while the glue had time to set.
We were careful not to smear any on the glass or top, and when finished it looked good and held for another year. This bought me some time to set aside some funds for a new top.
Now - this was about 5 years ago, and maybe a shop in your area has a tool to repair it. I'd at least check. But if they start talking top replacement it certainly wouldn't hurt to try and repair it first. If it doesn't work, you can always go with the replacement anyway.
Look at the bright side - it could have done what my C5 rear window did last July :ugh
:cry
Convertible Blues
Let me know how it turns out for you. Good luck!!
Jane Ann