a method for filling a dual fluid cartridge assembly which automatically bleeds air from the cartridge to filling and without extra steps or a vacuum as in known filling methods . in particular , the process relates to providing a dual fluid cartridge assembly which includes vents that bleed air from the cartridges initially and automatically closes the vents as the piston seal moves away from the vent . by utilizing such a self - bleeding cartridge assembly , the cartridge can be filled by a fluid dispenser without the need for shims , a vacuum or bleed plugs .