I push the break pedal I hear air coming out from behind the pedal

1999 NISSAN FRONTIER
250,000 MILES • 2.4L • 6 CYL • TURBO • 4WD • AUTOMATIC
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CHUCHO 69
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Does anyone know why when I push the break pedal I hear air coming out from behind the pedal? I already replaced the break booster, master cylinder, booster check valve and check all hoses for leaks but I still have the same problem.
Sep 10, 2016 at 6:18 AM
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KASEKENNY
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When you press the brakes the booster is what would make this noise unless you have some other vacuum leak. I would check the lines for a leak.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Below is the process from the manual as well on how to replace the booster. There may be an issue with bleeding the air out. Normally you just need to depress the pedal to bleed it but you may have also just received a faulty booster.

Please let us know if you have other questions. Thanks
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May 20, 2021 at 10:39 AM