Permanent glass adhesive is a unique product requiring an adhesive primer/promoter/catalyst. Use Loctite 37438, Permatex 81840, or 3M 08752 Rear View Mirror Adhesive. About 0.3ml is sufficient for one mirror, so don't waste your money on larger quantities. The mirror adhesives that are available typically bond for 3-5 years.
Mark the intended location of the mirror mounting button on the outside of the windshield using a grease pencil or crayon. Loosen the mounting screw and separate the mirror from its rectangular mounting button, paying close attention to how they fit together. If the existing button is plastic, replace it with a metal button; Dorman 76864 is an assortment of three metal button styles including GM. Using a new single-edge safety razor, scrape all old bonding residue off of the glass and the smooth, non-dimpled side of the mounting button, being careful to avoid leaving any scratches. Thoroughly wash the glass using an ammonia base glass cleaner and a clean dry rag. Make sure that you orient and place the button exactly where you want it since you will get only one shot at installing it. Once the button is firmly pressed against the glass and the adhesive sets (~30 seconds), the glass will crack before the button will dislodge! Follow the instructions included with the adhesive verbatim, including preparation, the use of the primer/promoter, the amount of time you must apply pressure to the button, and the recommended cure time before remounting the mirror. Don't rush it!
1
