If your car windshield is cracked, you need to change it out quickly before the crack gets worse and eventually causes the glass to shatter. The glass is held in place on the windshield frame by a rubber gasket running across the entire edge of the glass. It will take two people to safely remove the windshield from the car and install new glass with the gasket. If the gasket is very old, change it as well.
Remove all objects like the wipers and rearview mirror that will get in the way of the windshield's removal. The wipers are either bolted or clipped on while the mirror is attached by screws. Tape over the heating vents so glass shards won't fall into them.
Inspect the rubber gasket that seals the window to the frame. If it feels hard or is cracked, cut it away with a knife, pushing the blade into the rubber outside the glass's edge and slicing all the way around the edge.
Separate the gasket from the car frame if you plan on reusing it. Run a wood stick across the gasket's outer edge to break the seal between the rubber and the frame. This seal is only on the original manufacturer's windshield.
Push the window out from the inside. If the gasket is intact push gently at the top with your foot and the stick, but don't kick the glass. Have another person catch the windshield from the outside.
Clean the window frame and the dashboard of all dirt and rust. Remove the gasket from the old windshield if it is still usable. If you get a new gasket, remove its sealant and let it warm in the sun to increase flexibility.
Place the gasket onto the new windshield, making sure the thicker, heavier end runs along the windshield's inner side. Coat the gasket's outer groove with petroleum jelly and run a nylon cord along it. Both ends of the cord should stick out at least two feet from the lower center of the gasket.
Place the windshield onto the frame from outside the car, making sure the loose ends of the cord lie on the car's inside. Enter the car, grab one end and slowly pull the cord out of the gasket to draw the gasket's inner lip in place. Have the other person push on the rubber so it doesn't slip off.
Clean off all petroleum jelly left on the outside of the frame. Install the rearview mirror and wipers.
