When I press the brakes in a car, there is a sort of hissing, almost compressed air sound coming from the brake pedal. What causes that? - Quora
Can the brake booster cause the brake pedal to go to the floor? Also when the engine is turned on, a hissing noise comes from the booster especially when the brake pedal
![Does the power brake booster make a hissing or bearing noise until appling brakes which changes the pitch of noise? Does the power brake booster make a hissing or bearing noise until appling brakes which changes the pitch of noise?](https://www.justanswer.com/uploads/ebrock63/2009-07-14_203252_2009-07-14_142710.png)
Does the power brake booster make a hissing or bearing noise until appling brakes which changes the pitch of noise?
![My brakes is making a hissing sound (like air coming free) when I brake but it isn't affecting the brakes, what could it be? Could it be a leak maybe? : r/Cartalk My brakes is making a hissing sound (like air coming free) when I brake but it isn't affecting the brakes, what could it be? Could it be a leak maybe? : r/Cartalk](https://preview.redd.it/6z6dnd7n8j141.jpg?auto=webp&s=c46c6ba65c03943e21c511aa72916a59ca256259)