When I hit the brake pedal on my 2002 Volvo S-60, it sounds like a balloon is being deflated somewhere behind the dashboard. Any thoughts? Does this require immediate attention, or is it safe ti simply live with the sound?
The noise might be caused from the vacuum brake booster check valve or from a leak in the rubber diaphram within the brake booster. When it comes to the brake system, any unusual noises should be checked out for safety’s sake.
Tester
I agree. This sound is alerting you to a possible brake problem. Don’t ignore it.
A slight “whoosh” sound while you are moving the brake pedal is normal. If the some continues while you are holding the pedal (but not moving it), then you have a vacuum booster problem.