Drivers side drum brake doesn't feel like it's working

according to my haynes manual my proportioning valve is in my ABS. That's where all my brake lines go to directly. I can't find a seperate proportioning valve anywhere else. I disconnected the brake line from the hub, pumped the brakes and very little is coming out. I disconnected the brake line from the master cylinder and put my thumb over the hole and had someone pump the brakes and I got pressure. I didn't see anything in the new wheel cylinder, the lack of pressure seems to be coming before it gets to the wheel cylinder. Am I going to need a new master cylinder?

If the pressure is low to one wheel only, this isn't a master cylinder issue. You may have a partially plugged port in the ABS unit. Have you tried using a pressure bleeder?