P/S fluid is not so much for lubrication as it is for hydraulic pressure. You need the fluid in the rack to make it work. Air compresses, fluid does not. If you removed the fluid it would die quickly.
I'm a little confused. At this point, the pump has already been removed and the fluid is just sitting in the rack and lines. Are you saying that you need the fluid in the rack to make it work manually(without the pump)?