cyidi

My 2015 C180 has 37.500 miles and is driving me crazy. Every time I turn the wheel on turns that are minimally strong, or I am coming out of a parking lot, I get a humming noise that seems to be coming from the rear of the car. The mechanic inspected the diferential oil level and it is ok, he does not know what else to look for. Have looked everywhere and have not found a similar problem on threads. Please help.

Andy74

Did you Mechanic drove the car and heard the noise and still doesn't know how to fix it?

Hazemc180

if a ticking + humming groaning noise apparently it’s normal I’m having the same noises in my 2017 c 180 and they are telling me it’s the brake vibrating on the brake disks which is crazy because cheap cars like Kia … don’t have this embarrassing noises

W205C43PFL

To be fair, cheap cars don't have high performance brakes. That being said, yes it would be nice if MB at least insulate that sound.

Hazemc180

What the point of having hight performance brakes if they are going to make loud groining noises.

and I don’t think all MB cars make this noise, so it’s probably a design flaw is some designated model, which weird from a premium Cars manufacturer

W205C43PFL

Good question. The point of high performance brakes is that, to brake more effectively and safely at high speeds, which the main focus have nothing to do with sound. That being said, high performance brakes works the best and is the quietest during operation when bedded in properly when new. The main focus on high performance brakes is for the braking performance and not the sound. I hope that clears up any confusion.
Dealerships can replace squeaking brake pads and rotors as per good gesture though if you push hard enough, just remember to bed them in properly next time to minimize noise.
Here is a video explaining the bedding in process (video courtesy of another forum member here)
Edit: As to answer your question on why not all MB are making this noise it is because the brakes were treated differently when new.

Hazemc180

I changed all 4 brake pads 12 days ago ( I didn’t change to rotors even thought the front ones seemed that they need to be changed but dealer said no need to change them now) I didn’t do the bedding and I don’t think the dealer did also.

can I still do the brakes bedding now?

W205C43PFL

Sorry to tell you this but I don't think it will help much to be honest but hopefully we can figure out something together, can you tell me how loud is yours and which brakes on which wheel did you notice is the loudest? It may also help if you share your driving (specifically braking) habits. For example when they were new did you slam the brakes or feather it?

Hazemc180

The noise is pretty loud you can hear clearly inside the cabin with the Windows closed.

When I slowly release the brakes in D or when I’m gently holding on the brakes on a down hill ( underground garage) the voice is very loud but in the two described circumstances the noise only comes from the front rotors.

When I’m in D and holding on the brake and turn the wheel left and right the rear rotors are the ones making the noise ( tic thumb guuuh ) groining noise it’s intensifies the further I turn the steering wheel but this noise only comes from the rear when in D and a complete stop holding brake ( when I turn the wheel while in P there is no noise )

im not an aggressive rider I’m usually pretty soft on the brakes in red light and turns.

but I had a couple of occasions after changing the pads to hat I was going at hight speed and used the brakes to go down from 170 to 90 but that’s it.

Hazemc180

here are a couple of short videos:

W205C43PFL

Thanks for the videos. There is some surface rust I can tell but it should go away after driving a bit. I don't notice any warping on the rotors from the videos you posted either so that's good.
What kind of brake pedal pressure was applied? You could check this from the Dynamic select, vehicle data screen. Or you can give me a general idea, when you are riding the brakes in the parking lot at low speeds (such as the one in the video, were you pressing it hard or gently tapping it?) Does such sound appear at higher speeds at all?
For the second video, was your vehicle moving at all or was the drive selector in Park? Was parking brake on? Edit: Nevermind, you were indeed moving in the second video, I watched it again.

Hazemc180

I was gently tapping the brakes, this noise only comes up when driving at low speed ( when creeping in red light or when trying to park the car or when slightly tapping on the brakes in a down hill ).

I don’t notice the noise at higher speed( maybe only at the last second when coming to a complete stop at a red light you will hear gruught ( a small groin noise at the moment the vehicle stops).

The clicking groining noise comes from the rear rosters when in D at a complete stop while applying the brakes ( I didn’t replicate that in the videos thought) but never when the car is moving

W205C43PFL

You mentioned that you seen other MBs that doesn't do this, were they amg-line cars with the bigger brakes (like your car) (higher performance ones compared to the standard size ones the regular line has for example) The good news is that it is not a safety issue, your brakes functions as intended to bring you to a stop, it doesn't occur at higher speeds and there doesn't seem like anything is actually broken/damaged in the video visually.

Only if there are squeaking noises when you are braking at higher speeds is when bedding them in will help you. Don't worry too much and enjoy your car : ) Any surface rust will amplify this effect you are describing as well which I do notice on the brake rotors in your video.

Edit: If you really don't like the sound, try putting a little more pressure on the brake pedal or if it is easier, let the vehicle creep forward in stop and go traffic and not just reduce brake pressure (so basically braking while still allowing the vehicle move). Instead, simply remove your foot off the brakes until you are at the distance you want to stop from the vehicle in front of you.

Hazemc180

Yeah I totally agree with what you said the brakes work as charm no doubt about that, I just feel embarrassed when it’s squeaking while parking.

I noticed the rust also I think its because the was not driven for a while ( bought used from a dealership).

Do you think replacing the rotors will reduce these noises significantly as I’m noticing rust around and behind the rotors.

I rarely drive the car maybe 30-40 km / 25 miles per week max

i had the car for around a month now and I only put in like 200 km on it or so

drivr once or twice a week to get groceries that pretty much it.

W205C43PFL

I see, so you weren't the original owner. No worries at all, the only problem is we don't know how the previous owner drove the vehicle prior to him/her selling the vehicle to the dealership. We don't know how was s/he driving it when the rotors were new and how s/he were driving it daily.

Did you purchase this vehicle as a certified pre-owned? On the report, what was the stated thickness of all rotors and pads prior to you picking up the vehicle?

I don't really recommend swapping the rotors for a new set for the following reasons: 1. The surface rust is really not that bad (and will gradually get cleared as long as there is not a lot of moisture and you are driving it frequently 2. The improvements of the sound might not be as much as you hoped. 3. Your rotors as you stated has quite a bit life left and the thickness is yet to meet the minimum.

However, if the sound is really irritating you that much to the point that you can't properly enjoy your car (basically your enjoyment is hindered because of this) then it might worth changing the rotors and then following the bed in procedure. Otherwise I recommend just finishing these sets of rotors (finish as in replace when it meets the minimum thickness for safety reasons). An example of not being able to enjoy the vehicle properly would be the start/stop system, some people pay money to buy a module just to disable it and to keep it disabled every time you start the car (by default even if you disable auto start/stop, it turns back on every time you start the engine).

Hazemc180

It was purchase as a certified pre-owned 80000km 1 owner a women who traded it for a newer year model

I don’t know the thickness of the rotors and the pads when purchased but they advised replacing the brake pads and oil and filters and said that everything else is in order( it’s my first car btw).

I think I’ll just keep the rotors for now, maybe when the rust rubs off the noise will decrease

W205C43PFL

Congrats on your first car, good choice!

Now that is strange, one of the items on the CPO checklist include either replace the pads or to keep the old pads but they cannot be below 50% of usable life left. How come they charged you extra for that? Same goes with engine filter and oil, if service is due for the vehicle, then it should be done prior to selling you the vehicle. Mercedes have two types of services, Service A (minor service) and Service B (major service) and then switch every year, did they charge you extra for that? Depending on your country, service is always out of pocket but they shouldn't be selling you a vehicle without completing the required maintenance when it is due and then tell you to pay for it after you buying it.