Hi, after doing a grand search, I couldn't find anything related to this.
When I push the brake pedal, a blowing sound similar to a truck's air-brake appears. This "blowing" sound stays as long as the brake pedal is pressed, and goes away instantly when releasing it. It is similar to the noise a pressure hose makes when filling the tires up with air. I have a feeling it is a vacuum leak, but I am not skilled enough to know where to look.
If any one has any ideas, it would be much appreciated! <img src="/forums/images/graemlins/kewl.gif" alt="" /> I am supposed to go to San Francisco in two days, and this is my daily commuter.

Thanks,
Karl

Trace the hose out of the brake booster. It is in the engine bay on the drivers side. It is a black thick and round disk sitting vertically with the master brake pump sticking horizontally with a white reservoir with a blacktop. You probably hava a craked hose.

Good luck,

Javy

The truck runs normally otherwise? A cracked hse to the power booster would certainly be a large vacuum leak. If you need a booster, I have one reasonably. Check the hose first.

Thanks for the answers. It runs normally otherwise, the sound is not that loud and can only be heard when the window is rolled down. I had a person pressing the brake while looking in the engine compartment, and the sound comes from the drivers side like you said. It is around the AC compressor to be specific. Is the bower booster sitting on the frame or on the engine? Is it the black thing on the frame behind the driver side headlight?
I'll try to find the leaking hose tomorrow. By the way, am I looking for a hose or a metal pipe?
Thanks!

The booster is the round black thing on the driver's side (on the frame, on the firewall). The brake fuild reservoir and pump stick out of the booster.

Seems strange since you say the noise comes from near the compressor.

While someone is pressing on the brake creating the sound, I would try the broom stick method. Wood is a very good sound conductor. Place one end on the different parts and the other on your ear. Often you can follow it back to its loudest point. Then you have your spot. With a clicking or tapping sound it works great. It should work the same with air.