2 There are several types of sealer for rubber gasket windshields and backlights. The Restomod Shop uses Adcobond's R-900 sealer, which is gooey non-hardening black, available from auto body supply stores. It is very effective when used properly. There's also 3M's #08634 Windo-Weld Resealant for rubber gasket windshields and backlites, which is available from The Eastwood Company. We're also familiar with #08509 Bedding and Glazing Compound (do not get it confused with #08609, which is also a flexible, non-hardening sealer for rubber gasket windows). Sealer is injected into the inside groove in modest amounts.