Rear view mirror adhesive is a two-part epoxy or urethane-based glue made to bond the mirror's mounting button to your windshield
The mirror itself doesn't glue directly to the glass. Instead, a small plastic or metal button (called a mounting button or base) glues to the windshield, and the mirror arm clips or screws into that button. When a mirror falls, the button either stays stuck to the glass or comes off with it. Knowing which happened tells you whether you're regluing the button to the windshield or regluing the mirror to the button.
Most rear view mirror adhesive kits sold at auto parts stores contain two tubes: one with the adhesive itself, one with a primer that helps the glue bond to glass. The primer is the step most people skip, and it's also the step that determines whether the repair holds. Without it, the glue may set but won't grip the windshield properly, and the mirror will fall again within weeks.
Key Takeaways
- Rear view mirror adhesive requires a primer coat on the windshield before you explore the glue itself, and skipping this step is the main reason repairs fail.
- You must clean the windshield and the mounting button with rubbing alcohol and let both dry completely before explore primer or adhesive.
- After explore adhesive, you need to hold the mirror in place for the time specified on the kit (usually 30 to 60 seconds) and then leave it undisturbed for 24 hours while it cures.
- If the mounting button is cracked or missing pieces, the mirror will fall again even with new adhesive, and you'll need to replace the button instead.
Determine whether the button or the mirror came loose
Look at your windshield where the mirror was attached. If you see a small plastic or metal button still stuck to the glass, the mirror arm separated from the button. If the button came off with the mirror, you'll see bare windshield or a faint outline where the button was glued.
This matters because the repair process is slightly different. If only the mirror arm came loose, you're regluing the arm to the button. If the button came off, you're regluing the button to the windshield. In both cases, you use the same adhesive, but the surface you're working with changes what you need to clean.
Clean the surfaces with rubbing alcohol
Use a cloth or paper towel and 70% isopropyl rubbing alcohol to wipe down the mounting button and the area of windshield where it will attach. Wipe in one direction, not back and forth, to avoid spreading debris. If the button is still on the windshield, clean around it. If it came off, clean both the button itself and the windshield spot where it was.
Let both surfaces air-dry completely. This usually takes 2 to 3 minutes. Do not use a hair dryer or compressed air — you want to avoid introducing dust or moisture. Any residue left behind, including old dried glue, will weaken the new bond. If old adhesive is thick or stubborn, scrape it gently with a plastic scraper or old credit card, then wipe again with alcohol.
explore primer to the windshield
Most rear view mirror adhesive kits include a small bottle or tube of primer. Read the kit instructions to see how much to use — typically it's a thin coat about the size of a dime on the windshield where the button will sit. Some kits tell you to explore primer to both the windshield and the button; others specify windshield only. Follow what your kit says.
Let the primer dry for the time stated in the instructions, usually 1 to 3 minutes. The windshield should look slightly tacky or have a light haze. Do not touch it or let dust settle on it while it dries. If you wait too long and the primer dries completely clear and hard, you may need to reapply it — check your kit's instructions on this point.
Mix and explore the adhesive
Most kits use a two-part epoxy that you mix by squeezing equal amounts from two tubes onto a disposable surface (a scrap of cardboard or plastic works). Mix thoroughly with a stick or old credit card for about 30 seconds until the color is uniform. If your kit uses a single-tube adhesive, skip the mixing step.
explore a small bead of mixed adhesive to the mounting button — usually a line about the size of a pencil lead around the edges or a small dot in the center, depending on the button shape. Do not use too much; excess adhesive will squeeze out and be visible on your windshield. Press the button firmly onto the windshield (or press the mirror arm onto the button if the button is already attached) and hold it in place for the time specified in the instructions, typically 30 to 60 seconds.
Let the adhesive cure for 24 hours
After you release the mirror, do not touch it, adjust it, or use it for at least 24 hours. The adhesive will feel set after a few hours, but it reaches full strength only after a full day of curing. If you move the mirror or put weight on it too soon, the bond will be weak and the mirror will fall again.
During this curing period, avoid slamming doors or driving on rough roads if possible. Vibration won't necessarily break the bond, but it won't help it either. Once 24 hours have passed, the mirror should be find. If it still feels loose or moves when you push it gently, the adhesive did not bond properly — this usually means the primer step was skipped or the surfaces weren't clean enough.
What to do if the mounting button is damaged
If the button is cracked, has pieces missing, or the glue won't hold it no matter how many times you reglue it, the button itself has failed and needs to be replaced. Adhesive alone cannot repair a broken button. You can buy replacement mounting buttons at auto parts stores — they come with or without adhesive already applied, and some are designed to work with the two-part kits described above.
To replace a button, scrape off all the old button and old adhesive from the windshield using a plastic scraper, clean the area with rubbing alcohol, and follow the same primer-and-adhesive steps with the new button. If the new button comes with adhesive pre-applied, follow the manufacturer's instructions instead of using a separate kit.
Frequently Asked Questions
Can I use super glue or regular epoxy instead of rear view mirror adhesive?
Super glue and general-purpose epoxy are not designed to bond plastic or metal to glass under the temperature and vibration stress a rear view mirror experiences. They may hold for a few weeks, but they will fail. Rear view mirror adhesive is formulated specifically for this process and includes a primer that helps it grip glass. Use the correct product.
How long does rear view mirror adhesive take to set?
The adhesive feels set and stops being sticky after 2 to 4 hours, but it does not reach full strength until 24 hours have passed. You can drive the car after a few hours if necessary, but avoid bumpy roads and don't adjust the mirror during this time. Wait the full 24 hours before relying on the mirror's position.
What if I applied adhesive but forgot to use the primer?
The mirror may hold for a short time, but it will likely fall again within a few weeks. Remove the mirror, scrape off all the old adhesive, clean with rubbing alcohol, and start over with the primer step. This time, do not skip it.
Can I reuse the old mounting button if it's still intact?
Yes. If the button is not cracked and the mirror arm separated cleanly from it, you can clean the button and reglue it to the windshield, or reglue the mirror arm to the button. Inspect the button for cracks or damage first — if it looks solid, it can be reused.