If it is not, slacken screw (20) securing the control bar (16). Move the bar laterally (by means of the slots in the bar). Tighten screw (20) and check the clearance again. 6. Checking the self-levelling device. Before adjusting the headlamps themselves, it is advisable to check the operation of the self - levelling device. In order to do that : a) Put the vehicle in the highest position b) Remove the L.H. headlamp rim.