I once agreed with a lot of posters that say it is not the brake booster. It really doesn't make sense to be a booster. As another poster said tough the failure is internal to the booster and causes the pedal to feel long and soft. In my case the brakes would engage with good bite and as I stayed on the pedal the braking force would decrease. Made the car feel like it is on roller skates - would just not slow down consistently.