I have an '89 chevy 4x4 that has a leaking master cylinder. I have a repacement that I am planning to bench bleed and install. At the same time I want to flush my brake system by opening all of the bleeder valves to gravity bleed while keeping the reservoir filled with new fluid. I have read quite a few articles but haven't got a clear answer on whether or not doing this is a sufficient way of getting the all of the air out? Will the air trapped from the MC swap be removed by gravity bleeding? Any help would be greatly appreciated.