A cracked or broken windshield, either in the front or the back, is a dangerous thing to drive with. A damaged windshield must be removed immediately for replacement. The exact removal procedure may vary depending on the type of vehicle, but is always one that requires care and at least two people.
Breaking the seal
If you are removing the front windshield, first remove the rearview mirror and windshield removing screws. The following is the foreign metal or plastic molding, if the car has one, helping to keep the glass in place. This requires a special removal tool ornaments (any auto shop should have one) inserted under the molding to catch and release the clips. Place a towel over the glass to avoid scratching the glass tool as you use it. You may also need to remove a number of screws holding the trim with a Phillips screwdriver. Next is the rubber seal. Check the status of the board. If it is dry and cracked, cannot be used again, meaning you can cut through it (and have a replacement gasket when installing the new glass). Carefully insert a knife blade on the board, making sure not to hit the glass like diving through the gum. Cut all the way along the edge of the cup to the original point. If the gasket is in good condition, however, you can remove the glass still intact. Run a big stick across the board to break its adhesive seal; this is only necessary on the board manufacturer.
Push the glass
The windshield has to be pushed out from inside the car, and the assistance of another person is needed. While you are sitting in one of the seats, put the foot and the big stick against the glass. Push the window glass with both feet and stick. Do not put in the glass. Be very careful if the glass is cracked; keep your foot and stick as far away from the crack as possible. Your assistant should be placed on top of the hood, ready to catch the glass, as it comes out of the window. If the seal is intact and in good condition, pull it on the glass so you can install the new glass. In most cases, it is best to get a new board. If the board is cut, its outer edge is probably still attached to the edge of the window; removing the remaining piece of the window. Be sure to clean the edges before installing new glass.