Here is the way I do it. When you get a new or rebuilt MC usually they will include a bleeder kit made of plastic fittings and short peices of plastic tube. They screw into the MC and run the lines back into the bowls, fill with fluid and pump slowly until all bubbles are gone. that way you are sure the MC is full. I have a few hard line made up to do the same thing. Saves a lot of time and brake fluid.
