FEGELEIN

I have about 2,800 miles on my 10' 550 4 and the breaks just dont seem smooth. Almost a grinding type of feeling and sound. Maybe a grainy feel and sound, tough to explain. The sound insn't a metallic sound, its more of a sound like warped rotors make in a car. Anybody experiancing this? Maybe it's just the way it is?

FEGELEIN

I wonder if it has to do w/ all the salt and sand the breaks have come in contact with over this terrible NE winter. Its that type of a feeling and sound, graniny, sandy and salty. Maybe just needs to wear off.

konigstiger

MBUSA covers brakes (i.e.: rotors, pads, etc.), wheel alignment, and road force wheel/tire balancing under warranty for first 12 months/12000 miles have dealer check it out if they claim it is normal request a test drive with a comparable vehicle.

FEGELEIN

good idea. My salesman lives north of me and swaps cars w/ me for service on his way to work in NYC. I'll tell him to swap an E w/ me. Does the 350 have the same setup? I think the 550s have slightly larger rotors, but rest is same, correct?

mg-E550

a little bit but very minor. I was wondering if the cross-drilled brakes give a different response.

FEGELEIN

Dont you have the crossed drilled? All 550s dom from what I understand. So you experiance the same sensation as I do? Like a grainy / sandy feeling between calipers and rotors?

mg-E550

Yes I have cross drilled rotors. I would describe the feeling exactly as you describe, although it's not consistent- some days it's worse than others.

FEGELEIN

Gotcha, well my dealer is picking up the car at my house and brining it into service. They're giving me an 10' E350 as a special loaner. They don't loan Es, but I requested it so I could compare another E classes' breaking nature. Im a VIP there.
I'll post my comparison and the dealers determination asap, fyi. How many miles on yours?

FEGELEIN

UPDATE!

I have an E 350 loaner and definitely notice a difference in the smoothness of the braking. Definitely something is up w/ mine. I suspect it is defective brake pads.

jbean114

I too have recently noticed some unusual vibration in my brakes... Like going over a washboard as I slow down. I have about 7K mi on the car and it seems to be getting worse. The steering wheel shakes quite noticeably during breaking. I'm scheduling an appointment with the dealer later this week.

I would love to hear what the mechanics said after you get your car back and if they replaced anything.

Thanks!

303E550

I noticed the same thing recently too. I'm at about 4500 miles now. I notice a slight bump, bump, bump feedback from my brake pedal when slowing quickly. I plan on contacting my dealer to have them take a look as well.

FEGELEIN

Here is the "dealers" conclusion. after a test drive and 27 point inspection, no abnormal braking characteristics we experianced in the drive and no abnormal wear was on the pads, rotors or anything. They said since the car only has 3k on it, the breaks need to further break in. My father was in the car and noticed the "warped rotor" sound as well, yet I do not get a wheel shimmy or foot sensation of a warped rotor. Now that more are chiming in on this issue, it might be a bug they have to work out.Def bring them into the dealer, so it is logged in the database, this way hopefully a recall will result from enough people having the same issue. I drove a 350 w/ 9k on it and it was smooth as silk, it might be isolated to the 550 brake system, although I understand the 550 just has larger rotors.

dmikim

Sometimes I feel the same slight bump, bump. But I notice that very rare when I start moving slowly and it is not after I use "hold". Will bring it to SA when figure out when exactly it happens and in which conditions.

HIRABI

Why don't you take a Test Drive with the Mechanic duplicating your concern and point out the issues to him/her. Or allow them to drive and see if you can notice the noise and ask them if they feel it?? etc...

I had certain issues similar to your concern and after a couple of service runs, I finally asked for the Master Mechanic to Test Drive. Worked for me...Gl all the same!!

FEGELEIN

Good point, You had this particular brake issue resolved or are you referring to another issue?

FEGELEIN

Everybody please post your dealer results, this way if anybody has better progression w/ the issue, we can impress it upon our own service departments.

Boulder GT3

Try a 5 hard braking sequences. Up to 90 and hard brake to 20 x5. The bedding could help. Sometimes, especially on the larger brakes, they don't bed well from the start.

The brakes aren't the caliber of the Brembos on your 997 but they are pretty good. Doubtful there is a warp or defect. More likely bedding as mentioned or grime in the calipers and rotors.

If the re-bed doesn't work the next thing I would do is pull the pads and re-lube the shims.

FEGELEIN

Hi Boulder,

I want to try this, but please explain it again. You might have some typos in there.

konigstiger

Here is another accepted technique for breaking in pads:

Accelerate to approximately 35 mph
Brake using light to moderate effort to reduce speed to approximately 5 mph (do not stop)
Repeat at least 10 times allowing approximately 1/3 mile between cycles
Allow pads to cool

Boulder GT3

Right you are. That is a more proper method although not nearly as fun as going 90 and pulling it down. The reason I suggested the higher speed and more agressive approach is that these pads/rotors have some time on them. The slower speed method above is accepted for new pads and/or rotors.

Just some suggestions from bedding in pads by the cratefull for track cars.

Let me expand on the shims I mentioned. There are stainless shims between the pads and the pistons. They are a pretty close fit and if road grit and grime gets in there it can create some noise. It was a constant problem I had on a ML500.

HIRABI

No, not the same issue....I just felt my brakes were grinding a lot and the service reps always told me they were fine. But after the Test Drive, they discovered the pads to be faulty! So, don't always take their word...

FEGELEIN

Explain that method again.

Boulder GT3

Proper method described by Konig above.

My suggestion is more aggressive due to you having some wear on the pads already.

Run the car up to 80MPH and brake hard to 20MPH. Do that 5 times with a 1 minute in between. It will get the brakes very hot, use some material and the brakes are more than able to stand that amount of heat.

FWIW, of the many MB pads I've used I've never seen a bad pair. Issues with shims and the sensors but never the pads themselves. Often time the tech will say pads on the work order but what they really did was some work on the adjacent parts.

FEGELEIN

Will do, what did you mean by noise is the previous response? I don't mean that ear piercing squeak some cars make. It is a dull wop wop, that is only heard by the occupants. It's like a warped rotor sound and a grainy feel in the pedal. Again mostly under heavy braking, low speed breaking it is really undetectable.
I am e-mailing my tech advisor and this is what he had to say, he has been very attentive to my concerns.

The repair order states that the brakes were inspected. There were no
abnormalities found in the brakes. Your salesman did not feel anything abnormal when he drove the car in, as did the technician. If you are feeling this when braking hard at higher speeds, it is most likely the tires gripping the
road that you are feeling. The AMG sport wheel package will allow the tires
to grip the road harder, which can cause a grinding type of noise. Sport
tires normally transmit more road feel into the car. This is normal. A
different brand of tire may make a difference, for better or worse. Your salesman
indicated that you did not feel this same condition on his demo, which did
not have a sport package.
The brake inspection included tire removal and inspection of the brake pads
and rotors. I doubt your salesman or the technician drove the car hard. What Iwould recommend you do is come in for a roadtest with us so that we can
verify your condition with your driving style.

I expressed that I did not think it was the sport tire package, especially, since I have a 4matic that has all seasons. I do feel more comfortable about the visual inspection perfromed, but if it continues after I try GT3's method, I will swing it by and give him a ride.

FEGELEIN

Did the rep tell you they were fine after a breakdown / visual inspection of the components or just from a test drive?