Pump the brakes but fluid would not come out of the bleeder?

I have the truck listed above k-1500 5.7 r engine, 4l60e transmission. It has anti-lock brakes on it. The anti-lock light had been on for a couple months, but it was stopping just fine. That is until a rear wheel cylinder blew out. It has heavy-duty brakes. I replaced shoes, drums, wheel cylinders, and hardware on both rear wheels. When I went to bleed it I tried with a vacuum pump and tried jar with brake fluid in it and pump the brakes but nothing would come out. I thought that maybe the master cylinder was messed up from going dry when the wheel cylinder blew so I replaced it and tried to bleed it again. Still nothing I even tried to gravity bleed it left the brake line off for 36 hours not a drop. I went and bought a scanner that claimed it could retrieve the ABS codes and that it could auto bleed most cars. Sadly, mine was not one of the many most cars that it worked for. So, before I spent that or more on another one I started calling around on other scanners and it seemed like it is not on the scanners that cost less than $1,000. Now a Chevrolet 1/2-ton four-by-four you would think would be under the heading of most cars. It is not. Does anyone have any idea as to why the lesser scanners do not support it?