Hissing sound when letting off the brake
Thread Starter
Newbie
Joined: Dec 2019
Posts: 3
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From: Toronto, ON
2016 C 300
Hissing sound when letting off the brake
Hello Everyone,
I currently drive a 2016 C 300 with roughly 70kms on it. A few months ago, I noticed my brake pedal was making a hissing sound when let off (see attached video).
I’ve taken the car to the dealership many times, around 3-4 times. But, they deem the hissing sound to be “operational” and can’t find any “mechanical” issues with the brake booster. I’ve gotten a second opinion from a different mechanic, who advised it’s definitely the brake booster. Has anyone else come across a similar situation? Where the dealership deems the part to be “operational” and therefore doesn’t see the need to change/replace the part.
Update: Can’t seem to upload the video from my phone. Will post it tonight.
Thanks!
I currently drive a 2016 C 300 with roughly 70kms on it. A few months ago, I noticed my brake pedal was making a hissing sound when let off (see attached video).
I’ve taken the car to the dealership many times, around 3-4 times. But, they deem the hissing sound to be “operational” and can’t find any “mechanical” issues with the brake booster. I’ve gotten a second opinion from a different mechanic, who advised it’s definitely the brake booster. Has anyone else come across a similar situation? Where the dealership deems the part to be “operational” and therefore doesn’t see the need to change/replace the part.
Update: Can’t seem to upload the video from my phone. Will post it tonight.
Thanks!
Last edited by mak29khan; Dec 17, 2019 at 07:46 PM. Reason: Adding video
Member
Joined: Dec 2018
Posts: 199
Likes: 31
C400
It's "normal" in the sense that it is widespread, but it is a real issue that affects a large base of vehicles - the underlying problem is a leaking brake booster.
After taking the car in numerous times for this, and getting some great advice from others who have fixed this in the past, I can confirm that finally getting the brake booster replaced with a new superseded part completely fixed the issue (even at very low ambient temperatures).
One additional thing this corrected is a vacuum leak in the system which can cause a loss of power particularly when accelerating from a stop - would definitely recommend getting it replaced just for this.
After taking the car in numerous times for this, and getting some great advice from others who have fixed this in the past, I can confirm that finally getting the brake booster replaced with a new superseded part completely fixed the issue (even at very low ambient temperatures).
One additional thing this corrected is a vacuum leak in the system which can cause a loss of power particularly when accelerating from a stop - would definitely recommend getting it replaced just for this.
Member
Joined: Sep 2018
Posts: 140
Likes: 51
From: GR, Michigan
2015 Mercedes C400
It's "normal" in the sense that it is widespread, but it is a real issue that affects a large base of vehicles - the underlying problem is a leaking brake booster.
After taking the car in numerous times for this, and getting some great advice from others who have fixed this in the past, I can confirm that finally getting the brake booster replaced with a new superseded part completely fixed the issue (even at very low ambient temperatures).
One additional thing this corrected is a vacuum leak in the system which can cause a loss of power particularly when accelerating from a stop - would definitely recommend getting it replaced just for this.
After taking the car in numerous times for this, and getting some great advice from others who have fixed this in the past, I can confirm that finally getting the brake booster replaced with a new superseded part completely fixed the issue (even at very low ambient temperatures).
One additional thing this corrected is a vacuum leak in the system which can cause a loss of power particularly when accelerating from a stop - would definitely recommend getting it replaced just for this.
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