I have a product in my tool box , that I may have liberated from the body shop attached to the dealership where I worked , that may be what you need .
Here's the info off the tube .
Pro-Form ( A Teknol company)
Weather- Skin Mastic
Use to repair cut or torn weatherstrip gaskets .
I've used this on torn door seals, on my mini van , and I'm, 100% satisfied with the result.
But I don't know where you'd find it to buy any .