Paul106

Hi all,

my 2014 C250 Coupe Sport Plus has developed this rattle (or more like a sound of a nut or a bolt in a metal jar) which is outside of the car. It usually appears when driving around ~20..30 mph on a rough road. But it goes away when I engage parking brake while driving (just a little bit). I went to dealer twice with it with no result. They said everything is normal. It is really beginning to drive me nuts!

I would suspect this is related to parking brake cables. Has anyone ever had this? So far, this C250 is the worst car ever I had in terms of rattles and noises

Hm...I just thought - can brake pads rattle like that?

djprov431

I've got a 2014 C250 Coupe that doesn't make a sound..sorry you're having a problem with yours. I expect it would drive me crazy if I had what you describe. Can you not re-create the noise with a tech in the car?

Paul106

Yeah, I tried but they were listening for something louder. It is the same story with my panoramic roof rattle - the one I had after the famous W204 Coupe rear deck one. The techs did not hear it at first (and I think they thought I was crazy or just a jerk wanting to get a loaner) but then the guy said he drove the car for a week and that noise started driving him crazy as well. And then he found it (we thought it was roof insulation but it turned out to be the pano).
The whole experience was not pleasant (I hate to be a jerk customer) and I just don't have enough time to go throgh it again. At this point, I hope that with time the noise will get loud enough so there will be no question whether they hear it or not If anyone else had this problem and they know what the culprit is - then I can just go to the dealer and tell them exactly what to look for. The rattle can get really loud in the right conditions which are apparently hard to find around the dealership - but all around my apartment and work!

mriou

I have a similar noise on my 2010 C300. Same story - they couldn't hear it at the dealership - it's only apparent with the windows down though, and only over shallow manhole covers or tar strips/small cracks in the road. Ironically, speed bumps or larger bumps don't create this sound - is this similar?

I took it to a trusted mechanic who spent two hours (free) poking around and said everything is tight and safe so he didn't want to tear it apart in an endless search. It literally sounds like a tray of nuts and bolts being shaken, but again, only is "small", sharp front wheel displacements.

The car handles well and doesn't leak anything, but sounds ridiculous.

Paul106

Exactly! And the noise goes away once you squeeze parking brake even a little bit which makes me think that this is not necessary the parking brake assembly itself but may be something in the cables / levers which connect it. I have been using the parking brake and the noise is more audible now so I hope the thing will get loose enough for the dealer to hear it by the next service.

mriou

Boy that makes me laugh! That's what my own mechanic said, "Hopefully it'll get louder so we can pinpoint it!" I've never even touched the parking brake, so I'll do that judiciously tonight.

Sad Mercedes here couldn't find anything, but no surprise - in their "100-point inspection" I had them do after I bought it at a third party dealership, they missed the fact it had the wrong size (aftermarket) front rotors on - also picked up by my mechanic right away.

Anyway I'll try the parking brake thing and see.

Thanks, MMM

mriou

OooooK. I finally went for a drive today and it is definitely the FRONT brakes. There was no change when I engaged the parking brake, but it went completely silent under normal braking. I'm not sure why I didn't notice the before. I know for certain it's the front (does the parking brake only engage the rear disks?) so I'll be able to feed that to my mechanic before I head in yet again.

MMM

Paul106

Hmmm! The parking brake does not engage the disks - as far as I know there are two tiny brakes behind the rear rotors which are used by parking brake. I am very curious what your mechanic will find!

mriou

Fixed! It was very straight forward: some sort of $15 retaining bracket for the front left rotor that the dealer AND Mercedes both missed.