The weather stripping that surrounds the windows on your BMW does an important job of keeping moisture and liquid out of the car. It stops rain from pouring through the cracks between your windows and metal body frame and into your interior and also helps insulate the interior of the car when it is hot or cold out and you have the air conditioning or heat on. Over time, this weather stripping can crack and wear down, requiring its replacement.
Pry the old weather stripping out of its place with a slotted screwdriver. Wrap the tip of the screwdriver with the shop rag if you are concerned about scratching the paint on your car's exterior panels as you remove the weather stripping. Start from one end, and slowly work your way around the perimeter of the window.
Pull the old weather stripping out of place once it has been loosened, and run a shop rag between the window and body panels to clean out any remnants of dirt.
Align the new piece of weather stripping with your window, and gently tap it into place using your rubber mallet. Start at one corner, and work your way around the perimeter of the window, just as you did when removing the old weather stripping.
