1998 GMC , have replaced , Rotors , calipers , pads , front brake hoses, rear drums, shoes, hardware, wheel cylinders, hydro boost, and master cylinder. Still have very low pedal and won’t stop when a hard stop is needed. Have bled numerous times the brakes, at ports and factory ABS bleed. Also have bled the power steering and replaced the PS fluid. has any one got the answer or have been through this before. i have exhausted the things that i know.

 

I just went through the same thing with a 94 truck. It took a insane amount of bleeding to get a stiff peddle.

Are you sure you bench bled the master cylinder properly?

When bleeding lines are you starting with the rear passenger side and working your way up to the master?

 

After you are sure you have the air bled out take it down a gravel road and lock it up a few times, this will help a bunch.