Ok well i have a 96 blazer with rear drum breaks which i blew the rear end out, so i decided to swap the rear end out and added a rear end from a 2000 blazer rear disc brakes. i bolted everything down and put everything back together. started to bleed the system and it seems like not that much fluid is coming out and when i put the truck in drive the calipers aren't squezzing to stop the rotor. i heard i may need a new paportioning valve is this true. if so where is it located

 

and i also noticed that on 96 you can adjust your proportining valve

 

I am assuming ABS right? I did read somewhere that you may need a Tech 2 scan tool to open your ABS valves to get fluid out. Not entirely sure though.