Remove the rear side moldings. Using a windshield removing knife from the drain, cut out the urethane rubber that holds the glass to the frame. The most common knife is set at a 90 degree angle and has a short, flexible cable attached that is pulled by a handle. It takes a good amount of force to pull the knife through the hard urethane. A long razor knife is also used to work quickly through straight cuts.
Clean the old urethane out of the glass frame. Urethane windshield is difficult. You will need a sharp knife and patience to remove.
The pump with a new urethane putty gun. Urethane windscreen comes in metal sleeves and is available in auto parts stores. Clean new glass and glue application to help adhere to urethane glass.
Install the rear window. Install the rubber stopper at this time if necessary. Have a helper position of the glass, lower the lower position of the glass stop, and slightly tilt the top in place. Press down on the glass to put it in urethane. Install chrome moldings, if the vehicle has one.