Brake sounds

I have a 2002 saab 9-5. Recently I hear this air blowing sound when I’m driving. When I step on the brakes, the sound stops, when I release it comes back again. Can anyone tell me what this is before I bring it in and if it’s dangerous?

Thanks,

emilystrange

It sounds like a leak in the vacuum system. This could be a safety issue and should be addressed now. It could get worse suddenly and you might loose power assist to the brakes and the brakes will require a lot more pressure to stop your car.

It may be as simple as a loose vacuum line, but it also may be a more expensive part.