rear brake problems

i have noticed that since i put the disc brake rear end from a iroc under my rs its not getting good enough pressure to the calipers. i put it on jackstands and had my brother press the brake pedal to the floor and i was able to turn the back wheels by hand. it had some pressure but its weak pressure. whats wrong, i changed everything out to adapt the rear brake calipers.

Did you also change out the proportioning valve and master cylinder?

nope, id say thats my problem

you might want to bleed the brake system you might have some air in there.

You sure its not just air still in the line?. I know that I have heard 4th gens don't need the proportioning valve changed but I am not too sure on 3rd gens.

John

i have never changed a master cylinder, or a proportioning valve, is it hard?