To replace the rear glass on a pickup truck, clean the glass and the surrounding area to remove contaminants, and use a razor knife to remove the weather stripping around the existing glass. Push the glass outward from the inside of the truck to remove it. Use the razor knife to remove the urethane from the glass frame, apply urethane primer to the frame, and place a bead of urethane caulking around the frame. Press the new glass into place.
Allow the urethane primer to dry before applying the caulking, and allow the urethane caulking to cure for two days before driving the vehicle.
To install a gasket-style rear glass, clean the glass and surrounding area, cut the gasket around the glass using a sharp knife, and remove the glass. Place woven rope around the perimeter of the new glass, with the rope in the center of the gasket, and allow the ends of the rope to overlap by several inches.
Set the glass into place, and have an assistant hold the glass in place from the outside of the vehicle. Pull one end of the nylon rope gently from the inside of the truck to force the gasket over the metal sealing lip. Continue pulling the rope until the gasket is sealed, and remove the rope.