It will certainly take a long time to bleed your brake system if you didn't pre-bleed the master cylinder off the car. This allows the master cylinder to be free of air, thus making it easier/quicker when you bleed your entire brake system. Assemble the resevoir on the master cylinder off the car, and fill it with brake fluid. I would put it on a bench vise so you can pump the cylinder with a screw driver until the ports squirts out brake fluid. There should be a couple plastic nipple fittings that should come with the new cylinder. Just make sure you install them in the ports before you start bleeding them off the car.