Back in April I had my front brakes replaced, and the next day I noticed that when I was stopped I could hear a bubbling sound and the brake pedal would vibrate slightly. So I took it back to the shop and the guy came out to check it out. He gets in the car and mashes the brake pedal, and I ask him if he can hear the noise, he of course says 'no'. So he continues mashing the pedal, then all of a sudden this huge white cloud belches out of the exhaust and the engine starts to stumble. I'm standing there with this look on my face like someone just kicked me in the nuts. Then the guy says "wow, thats not good" (no shit sherlock). Turns out my brake booster was bad and full of brake fluid, and since it runs off of vacuum from the intake manifold, it was leaking brake fluid into my intake, which sped up the bhg process. That experience totally sucked ass, but at least I learned something from it. If you are losing brake fluid, and you cant find the leak, check your brake booster.