General brake question

I have a car (a 2000 XYZ with power brakes, no ABS, disks in front, drums in back) and the front brakes locked up while driving and were smoking. So I replaced the rear brake shoes, rebuilt the front calipers, inspected the front pads (they were new), inspected the metal brake lines (in good condition), and replaced the front rubber brake lines.
So when I went to bleed the brakes, the fluid level in the master cylinder reservoir is not moving at all, the pedal goes to the floor, and the fluid in the reservoir is cloudy. Little to no fluid comes out of the bleeders. I've been trying to bleed the brakes for two days with no results ( tomorrow will be day three).
So my question is: might the car need the master cylinder replaced? I hate to keep throwing parts at it like a mechanic shop would do, because it's getting expensive. But all the symptoms don't point to a faulty master cylinder.