just worked on my brakes, i replaced front calipers, rear wheel cylinder and two stainless brake lines, also i bought a kit to convert the pm to vaccum brakes. i also changed the master cylinder out of an 86 monti ss. the problem is now that the car stops but the brake pedal still goes 1/2 way to the floor before it gets hard, i bleed the brakes numerous times no air. is this vaccum booster correct?