Methods of reducing air within a stent graft delivery device are disclosed, utilizing various flushing techniques. A port in a manifold that includes a pusher catheter coaxially disposed about a guide wire catheter is flushed. A portion in a sheath hub that excludes a longitudinally extended outer sheath coaxially disposed about the pusher catheter is flushed with a flushing fluid and/or a blood soluble gas, such as carbon dioxide. The guide wire catheter is also flushed.