2000 Chevy Blazer Brakes Problem

I have a 2000 Chevy Blaver. Somtimes when I brake the pedal will move slightly toward the floor (not very far) and stop the vehicle (as expected), but most of the time when I stop the pedal will move all the way to the floor and the brake light will come on (but the vehicle does stop). At first I thought it might be the master brake cylinder but once the vehicle is stopped the brake pedal doesn't ease toward the floor like a master brake cylinder leak. The pedal is just inconsistent, sometimes it brakes normal and sometimes the pedal moves real close to the floor and the brake light comes on. Any ideas?

Thanks,

Zach I would check your vacume to your brake master cylinder. Even a small leak that would not cause the engine to idle rough would cause the problem you are talking about. If this does not fix it i would look into the brake master cylinder itself.

you can buy a rebuild kit for these very cheap and it is very easy to do.

Good Luck