Hi guys, just putting the car in the shed before and I noticed that if I hold my foot down on the brake pedal hard, I can hear a hissing coming from the booster...the hell is that all about? I've never noticed it before - seems like its just started but if I push down with less force it doesn't do it... you know how with older falcons when you first press the brakes with power brakes they hiss for a second or so? Its like that but keeps going....other than that brakes seem normal, although I've not driven it since I noticed this noise....any ideas?

update - just took it for a drive, brakes work 100% fine, with regular pressure to stop even aggressively - no problem. Its only if I push the pedal a bit harder once its stopped I can hear the hissing...thoughts?

Does the engine pick up a few revs????
Sounds like the booster is on it's way out.

nah, i was listening for that.. nothing. I mean, I hate to say it but yeh I think the booster is on its way out (even tho performance is completely unaffected) - to be quite honest it may have been going for quite a while, never really noticed it before...just happened to press the pedal a bit harder and can just hear it so I'm thinking pinhole in the diagphram ...