If the jack is inverted and a pipe is run from the pump intake to the 'top' of the jack an external reservoir is not needed as long as the jack bottle is kept filled to the level of the fill point. I found that the standard vicosity oil used in jacks is a bit too thick and the pump may not draw it up. The purpose of the air bleed is to allow any build up of pressure to escape, otherwise the bottle 'top' seal may blow out. This was my Ver. 1.1. I now use an external pump and reservoir but still have a bleed point.