I'm having a problem with my brakes. There'* alot of travel on my brake pedal so I checked my brake fluid and it'* full, I then checked my pads,rotors and shoes and their also fine. I then bled the the system and still no change, But I noticed that when I step on the brake pedal I hear a whoosh sound(almost like air escaping) coming from the under the dash area of the car,so I think it may be the brake booster. Please any opinions on my problem would be greatly appreciated.

I'd agree on the thought of a booster. There shouldn't be a whooshing. Any loss of braking like a bad master cylinder or harder braking?

The boosters job is to add the power to the power brakes.

all I can say is the brake pedal doesn't feel very firm when I press down on it. But it'* the travel in the brake pedal that that'* making it hard to stop. I don't know if you have ever driven a car with badly worn brake pads and it seems like you have to push the brake pedal almost to the floor to stop the car,that'* what it feels like.

If it is the booster how hard is it to change out and should change the master cylinder at the same time?