For the removal and installation of the regulator of E30 door models, begin by taking off the door panel and following it up by the removal of the window glass together with the detachment of the wiring harness of the regulator motor. After that, remove the mounting screws from the door panel and extract the regulator from the door cutout and the installation is performed in the reverse manner. For E36 models, initial step will be the removal of the door panel; for four door models remove the window while for two door models, pull the glass of the window from the regulator and unwind it. Then take out the interior door handle, then drilling out mounting rivets, also unscrew the end of the arm and taking out the regulator. Installation is done in the reverse order, by removing the rivets and replacing these with M6x10 bolts, washers and matching nuts, the fasters should preferably be thread locked.