2003 Ford Thunderbird how to bleed brakes

2003 Ford Thunderbird mileage: 28,000. I just changed the rear brakes and calipers on this car. I went to bleed the brakes, but I'm not getting fluid to the rear calipers. These are hydraulic brakes and I think there is a procedure to accomplish this. I have tried to reset the proportional valve but that didn't seem to change, also tried to crack the front bleeders while applying pressure to the peddle. I have had the engine running and not. I have talked to several shops and many say you need to do several different functions to reset the system. If you have any information on this procedure, I would really apreciated it.