# Blowing sound when pushing breaks just bought new yesterday



## jonwalden68 (Nov 18, 2013)

It does it only when brake pedal is first pushed down last 10-15 secs then goes away then does again as soon as you push pedal


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## Aussie (Sep 16, 2012)

That sounds like it could be a leak from a vacuum line. Can you open the hood and get someone to push the pedal and try to identify where the sound is coming from. Watch out for moving belts, pulleys, fans etc. I would definately take it to a dealer just to be safe.


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## jonwalden68 (Nov 18, 2013)

It does sound like a vacuum line but it a exact amount of time each time you touch the brake pedal 


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## Robby (Mar 1, 2013)

You are hearing the electric vacuum boost motor cycling.....will do it with each brake application.

Rob


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## jonwalden68 (Nov 18, 2013)

Yes sounds exactly like you said 


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## KyRebel928 (Apr 21, 2014)

What is the vacuum boost? 



Robby said:


> You are hearing the electric vacuum boost motor cycling.....will do it with each brake application.
> 
> Rob


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## Robby (Mar 1, 2013)

The power brake booster (large cylinder that the master cylinder is bolted to) requires vacuum to operate.
The vacuum is supplied by the vacuum present in the intake manifold.
A turbo charged engine will, when the turbo is operating, have positive pressure in the manifold......therefore, there is no vacuum available for the brake booster.
The Cruze uses a electric vacuum pump to provide the vacuum to the booster anytime the pressure switch sees low vacuum.
You will hear the pump run with each brake application if it is quiet enouph around you.

Rob


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## Merc6 (Jun 8, 2013)

You will also hear a scrape sound and possibly feel a vibration for the ABS self test between 12 and 13 MPH on the 1st drive. Literally between 12 and 13 mph, riding 12 mph in a parking lot you won't hear/feel it happen yet. Just figured I say that and save you another post.


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