Alero Brake Problem

I have a 2000 Olds Alero w/ a 3.4L V6. When I push the brake pedal down, I hear air noise. I was going to bleed the brakes first, and then replace the master cylinder. Am I on the right track?

hello, how do breaks feel/work ok?check the brake booster for vacuum leak
possible check valve in booster.

The brakes barely work. Where is the brake booster located?

they hardly work.like there's no power assist??brake booster is mounted on firewall in front of driver in the engine compartment.check valve is the plastic valve that the vacuum hose connects to on booster.see if u have vacuum there.if not check vacuum sorce at intake manifold.with engine running unplug vacuum hose engine should stall if not you dont have
enough vacuum.

The brake pedal pushes all the way to the floor and does not stop the car.
The engine almost stalls when you push the brake pedal to the floor.
I really appreciate all of your input.

if you have checked the fluid level & its ok & you have'nt done anything to the brakes. it sounds like the master cylinder is bad like you were thinking in the first place.good luck!!