I feel no spongy or mushy feeling in the pedal. Its firm the whole time.

 

The brake fluid can impact how the brakes engage or lack thereof. My 04's brakes felt like no matter how hard you "hit" the pedal and it would never come close to locking up the wheels or even engaging the antilock. The fluid was over 5 years old and dark. I replaced the brake fluid, flushed it all the way out to all 4 calipers until it was clear and it made a world of difference. I also replaced all the rotors and pads with EBC slotted / dimpled (not drilled) rotors with their Extra Duty Truck and SUV pads, and it made the brakes even better. Something else I was thinking of is the rubber portion of the brake lines, as they age (mine = 13 years old) they are not able to hold the pressure and they "balloon" a bit. This can also reduce braking effectiveness. Now that I am thinking about it, I will be replacing my brake lines before winter with some braided SS lines.

 

Another that usually gets missed in a big brake system overhaul is the calipers. No matter how much you flush there is still some old fluid trapped behind the pistons. The only way to truly clean that out is to basically rebuild the calipers (or replace them). They are actually pretty easy to rebuild - google it if you are interested.

 

This issue has been resolved. Not sure what the problem was or where the original brake boosters were sourced from by the mechanic. A new genuine GM brake booster fixed the issue. The brake fluid was flushed as well.

 

Thanks for the update. One reason I stick with OEM parts. And never rebuilds.

Sometimes the savings on aftermarket is not worth it.