Free the top panel by disconnecting the top half of each of the top panel's hinges. With a helper, slide the top panel out and let the roller fall out on the opposite end. Then, remove the second panel's hinge and roller on one side, disconnect the hinges and slide the panel out. Repeat the process for the remaining panels. Setting the Panels First scrape away any caulk left by the old doorstop molding and measure for the new stop.
Most molding comes with a vinyl weatherstrip insert.
Cut the new stop to length and lift it in place. Nail the new stop molding to the header. Install the two vertical tracks at the same height. Set one track, then measure its position to place the other. Install the horizontal tracks above the vertical tracks.