Hey all you 40 guys...'77 FJ40 - when I press the brake pedal I get a whooshing sound like air being pressed out of a diaphram. After the pedal goes down a little ways then the brakes engage and the old girl stops. If I repeatedly press the brakes then there is less whooshing and more brake engagement. Is this a sign of master cylinder blowby? After the brakes engage, the pedal elevation holds steady, it doesn't drop to the floor.