Hissing brake sound on '09

[s_c5519]

Truck has 2,000 miles on it, it's been doing it since I bought it. When I apply the brake there is a slight hissing sound coming from around the same area. It seems to go away if I press the brake 2 or 3 times or more immediately, but it does it every single time on the first press... Also I feel a tiny amount of feedback on the brake pedal when this sound happens...

Does anyone have an '09 and possibly an '08 and can check if yours does the same. I brought it to local Hummer dealer and 2 different people checked it out and said it was fine, that is normal, and they hear that on other different '09 vehicles. I forget what they said it was, but they said it was NOT a vacuum leak, which I was surprised to hear. I have had an '05 and an '07 and it definitely did not do it on those two, so I am guessing/hoping that is a normal thing on the newer H2's. The next closest Hummer service is about 50 miles away so I would rather not drive there for nothing too...

[dvl57]

initial squeeking sounds are normal on my 08 H2.
dealer said that's normal...and the brakes should last a long time.

[s_c5519]

dvl, are you getting a squeaking sound or a hissing, air sound? My sound is like an sssssssss... and it sounds like it's coming from the inside cab or firewall, not the outside brake pads...

[twr]

hi my 08 doesn't make any noise inside when you hit the brakes. If you push the brake pedal with your hand with your head down there still no hissing noise. This only happens when you hit the brake?

[s_c5519]

Originally Posted by twr

hi my 08 doesn't make any noise inside when you hit the brakes. If you push the brake pedal with your hand with your head down there still no hissing noise. This only happens when you hit the brake?

Hi yes only with the brake. It just can't be normal, I will bring it somewhere else. Thank you for your replies.

[s_c5519]

ok, looks like I have the answer?... I called the service dept at Legends Hummer in AZ and he said the hissing is normal and comes behind the firewall... The '09's no longer have the hydro booster that connects into the brake system. It is upposed to be a better setup. The ones ('08 and under)with the hydro booster would leak and make whining noise when turning...

Sound right? any brake experts here?

[Saudi H2]

I have the same sound on my H2 sut 2009

When the brakes get warmer the kinda go away !