E350owner

My 2014 E350 is making an odd sound when breaking. I have been to the dealer. They said everything is fine. I have done the 50 to 0 fast breaking several times to clean any glazing. When the car has warmed up and been driven for awhile, the brakes make a two tone flute like sound (like an Uh Oh) when the brake pedal is depressed (from start of pressing pedal to about half way). The sound is coming from under the steering wheel. There is no sound outside the car (we checked). I can get the sound to stop if I pump the breaks a few times. It then comes back after driving and braking a few more times. The sound is not like screeching worn pads. It sounds more hydraulic in nature - like pressure is being released or a piston is letting off steam. I can actually make the tone oscillate up and down by adjusting pressure on the brake pedal. Has anyone experienced this?

PeterUbers

I don't have anything like this but it sure sounds like it's something to do with the brake fluid/pump

E350owner

Interestingly, I ran the car last night and turned off the eco drive. The braking sound stopped. What would be connected to the brake pedal as part of the Eco start stop that could be making the noise?

E350owner

it was the brake booster assembly gone bad.

GLENN S.

A 2014 booster defective? I thought with noise under dash, yes, but not on one that new.
Hopefully it was warranty

Olympuss

I will really appreciate if you could have a look at this two videos and tell me if its a similar noise.

I'm a bit desperate because i can't find a mechanic which could figure it out what's wrong with the car.




https://vimeo.com/440024147

https://vimeo.com/440051110

https://vimeo.com/440051262

https://vimeo.com/440051193