RichNY

shang12

I have the same issue with my c400, on cold days driving and when releasing my foot of the brake pedal I hear this "hissing sound" its like a air vacume sound..i have made a note of it and the dealer couldn't duplicate it so I took a video of it so hopefully we can figure out what the issue is (if at all) but strange that only on cold days it happens not warm days..

you said your brake booster was replaced a year ago, was it due to this issue or did you come across this issue?

thanks

RichNY

RemmyZero

It's been brought up here before and is quite normal in the cold weather.

https://mbworld.org/forums/c-class-w...al-normal.html

shang12

well i have my c400 in the shop for them to take a look at this issue, so i have a 2018 c300 loaner car and this doesn't make that hissing air sound when you are pressing and releasing the brake pedal on cold days so i know this isn't normal or it would have done it on this car as well..

RichNY