DIY Front Windshield Window Replacement

If a windshield has been cracked or otherwise damaged, you need to replace it before the damage becomes greater. The exact replacement procedure--along with the actual size of the glass--will vary with each vehicle, so consulting a mechanic or auto glass expert is always a good idea. Replacing windshield glass will take at least two people.

Removing the Old Glass

Remove the rearview mirror from the inside of the glass and the wipers from the outside. Both of these are usually held with screws you must remove, and you may also need to rock the wipers back and forth to loosen them. Some cars have a plastic or metal trim bordering the windshield. You need a trim removal tool from an auto supply shop; remove the Phillips screws holding the trim and then slide the trim tool underneath the trim to release its clips. If a rubber gasket is holding the glass in place, you can use it again; for the original gasket, running a large stick across it will break its adhesive seal. If it is dried or cracked, cut it away by driving a knife into the gasket--make sure you don't hit the glass--and cut it along the edge of the glass. Push the glass out from inside the car, pushing your foot and the stick against it. Never kick the glass, or it can break. Another person needs to be on the hood to catch the glass as it falls out. You can then remove the full gasket from the glass or any remaining glass parts from the windshield frame.

Installing the New Glass

Be sure to wipe away all rust and corrosion from the windshield frame before you install the new glass. If you are using a new gasket, leaving it in a warmer environment for 30 minutes to an hour will help soften it. When attaching the gasket to the new glass, the gasket's thicker end goes along the glass edge. Now coat its outer groove with petroleum jelly and run a nylon cord around it; you need enough cord so both ends stick out after they meet each other at the bottom center. As you place the glass on the frame from the outside, make sure those cord ends go into the inside of the car. Then get back in the car and, while your assistant pushes on the glass from outside, pull one one of the cord ends so it pulls the gasket's inner lip in place. Once you clean away any excess petroleum jelly from the surfaces, replace the windshield trim, wipers and rearview mirror.