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Whooshing When Applying Brakes Quickly

Brake Noise Air

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5 replies to this topic

#1 OFFLINE   mikemusky

mikemusky

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  • My C-MAX's Year:2013
  • Current Vehicle:C-Max

Posted 17 August 2018 - 11:32 PM

Hello All,  I just purchased a 2013 C-Max Energi and had a question.  The car came with a 100 day warranty and I am not sure if I have a problem or not.  There is a $50 deductible and would hate to throw it away if there is nothing wrong with the car.  The car has 27K and is very clean.  I noticed a whooshing sound when I quickly applied the brakes today (think of a brake check where you quickly tap the brakes).  It was a quick whoosh as if air was being released.  I can recreate the issue but it does not happen under normal braking.  I've had the car for a week and this is the first time I've heard it.  Is this normal?  Any help would be greatly appreciated.









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#2 OFFLINE   SnowStorm

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  • Current Vehicle:C-Max SE

Posted 18 August 2018 - 06:18 AM

Does it only happen after being parked overnight and then only the first time (or first few times) brakes are applied?  My car is normally in a garage but there have been a few times when I have heard what could be called a whooshing sound the first time I applied brakes (end of driveway) after being parked outdoors.  I have assumed it was a bit of rust on the rotors from sitting outside on a damp night.  Of course I don't know if its the same issue - just my experience.  With light braking in a hybrid, regeneration is used but the friction brakes get applied when the car is almost at a standstill since no regeneration is possible if the car isn't moving.  It seemed that this possibility explains my experience.


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#3 OFFLINE   mikemusky

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Posted 18 August 2018 - 11:17 AM

SnowStorm - thank you for responding.  I think this is something different.  I can repeat it over and over again with a quick tap on the brakes.  Since I got the car, I have been focused on regenerative braking but last night a cat ran out in front of the car and I quickly tapped the brakes.  It only happens when I quickly apply the brakes.  Thanks again, Michael

#4 OFFLINE   Plus 3 Golfer

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Posted 18 August 2018 - 02:13 PM

I believe a quick jab of the brake pedal quickly opens the valve to the atmosphere in the brake booster and we hear a large, quick volume of air being drawn into the brake booster due to the vacuum on the other side of the diaphram. This in rush of air is what gives the "boost" to the push rod and makes pushing the brake pedal in easier.  Under normal braking (slower push of the brake pedal), the push rod take a longer time to reach the same positon and one does not hear the slower inrush of air.  

 

As far back as I can recall, my car always did this since new. 


Edited by Plus 3 Golfer, 18 August 2018 - 10:30 PM.

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#5 OFFLINE   jestevens

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  • Current Vehicle:C-MAX SEL Hybrid

Posted 20 August 2018 - 07:44 AM

I think I've heard that noise during emergency braking.  Last time was when someone driving a sedan in the left turning lane swerved wide in my lane, looked like they were about to cut me off and then they turned left..


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#6 OFFLINE   mikemusky

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Posted 20 August 2018 - 03:04 PM

Thank you all!








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