2002 Audi TT "hissing sound put brakes" Questions

...hissing sound until i let off the gas. I switched back to the stock dv with the same result, Either one of your valves isn't reconnected/reassembled properly or something else came apart . . . the ...

...hissing sound Put new brake pads & bled them. still no brakes & making a hissing sound. What could be wrong?? where is hissing sound coming from under hood or behind tire the brake booster is ...

...hissing noise when I put on the brakes, which still work very well. There is no hissing when my foot is off the brake. The hissing is louder inside the cab than outside, it sounds like a vacuum leak. ...

...Hissing sound once the vehicle is started there is a constant hissing sound coming from under or behind the dash on the drivers side, until the brakes are applied. it only goes away when the brake ...

hissing sound if I put my hand around the rubber boot on the booster arm under the dash. I shut the engine off and removed the hose from the intake, when I pulled it from the booster I think the sound

...hissing/air noise when depressing the brake pedal. Also the brakes are almost no exsistent. I am pretty sure it is the Master Cylinder but someone was telling me could be a vacumm switch? Any ideas ...

...sound almost like an air leak coming from the front drivers side wheel. Its not an air leak CHECK THE TIRE AIR STEM.I HAVE SEEN THEM LEAKING.I HEARD A HISSING NOISE TOOK TIRE OFF SPRAY SOAP WATER ...

as though the diaphragm on your vacuum assist has ruptured. This will cause a hissing sound and less brake you may also notice a change in the engine idle speed or a rough idle until the hissing stops

...hissing sound after I replaced master cylinder. I fixed brakes but motor keeps running rough and sounds like have a vacuum leak? Question edited for clarity. Question moved to model category. Yes, ...

...hissing sound. start checking and wiggeling each line u can find especialy around intake manifold and brake master cyl. for the hissing sound to change if u have a gauge and manual u can check vacume ...