My dealer just replaced the front rotors on my 2011 E550 due to excessive runout. This was at 24K+ miles! I've never had to replace rotors on any car that I've owned at such an early mileage. Anyone else with this experience? BTW, the dealer did this for no charge as they had never heard of it either.

 

Probably not warped, but residue will bond to the rotors, causing the pulsating. They must be getting hot or weren't bedded in properly. Usually the first thing I do with a new car is bed the pads in properly. I don't agree with the owner's manual of applying them gently, which leads to a lot of initial heat when breaking them in. What was the charge if you had to pay? May be a weakness in the cooling of the brakes so out of warranty may be pretty costly.

 

I read about this happening quite a bit with the E550's.

 

It was excessive runout, not improper bedding or being abused. There was NO charge for the repair.

 

Wow...24K miles ? I've never heard that low mileage for change of rotors. It should last at least 40K-50K miles. Are you permanently pressing on a brake pedal ? Applause to your dealer that he did it for free..

 

Nope. The total wear on the front brake pads was less than 20%. Most of my driving is on the interstate. Like I said, I've never, ever replaced rotors in less than 80K miles on any car that I've owned. I'm really glad that I paid $72K for a vehicle whose rotors warp at 24k miles and additionally with the interior wood trim that had to be replaced due to fading.

 

My front rotors were replaced at 12,400 miles. Under warranty. Time on car was about one year.

 

I think you'll find that a lot of 2011 E550 (and E350??) cars have had this problem. All four of my rotors failed the runout rest horribly, at 9,000 miles, and the dealer replace four rotors and all pads.

I, personally, think all this talk of "bedding" the brakes on a new car is sadly misplaced. The dealer says they are "bedded" at the factory, and by the techs when the rotors/pads are replaced (as so noted on the service document).

I've driven 9 new cars with disk brakes for the last 36 years, by multiple conpanies, and I have NEVER experienced any kind of unusual brake wear or pulsing, PERIOD. Then I buy a $70,000 car and the brakes pulse like crazy, straight out of the dealership. I give them time to "wear in" and no joy. (Oh, even driving dozens of cheap Korean, Japanese and US rental cars all over the country I have never had such pulsing!)

IOW, Mercedes has a SERIOUS problem with E550 (at least) brakes.

Now at 18,000 miles, the brakes squeak like crazy at parking lot speeds, forward and reverse. WHAT AN EMBARRASSMENT in the heavily attended shopping center in my very upscale neighborhood, just loaded with (current and) potential Mercedes customers. People ask, "Do all Mercedes cars sound like THAT?" I don't know what to say - - - maybe they do???

I took the squeaking brakes to my dealer and all that happened was the techs (and by position, the service writer) read me the riot act about not riding the brakes. In 30 years, since my last stick shift, my left foot has never left the floor! They then say the rotors are dirty and clean them. The brakes squeak as I drive the car out of the dealsership.

Do I think Mercedes has serious brake problems??? YOU ARE DA**** RIGHT I DO! Am I P***ED about it? YOU ARE DA**** RIGHT I AM! Is Mercedes getting a black eye in my neighborhood because of it?? YOU ARE DA**** RIGHT THEY ARE! Has Mercedes lost sales because of it? ONLY A FEW THAT I KNOW OF! (So far . . . We're a tight neighborhood of only 6,000+. Word moves around very quickly.)

(I must add. I consider any irregular performance by brakes, especially pulsing, to be a serious SAFETY PROBLEM. Apparently Mercedes does not. Somehow I get the feeling that every 2011 E550 that enters a dealership should be tested for runout, or at least for pulsing. If for no other reason than for the legal exposure.)

 

My brake pulse and I'm at 10 months in with around 8000 miles on an E350. I don't ride my brakes and followed the owners manual. I was quite surprised when that started to happen. I assume that it will be covered under warranty when I go for my 1 year service.

 

Almost 32k miles and no issues on my 2011 Bluetec so far. Interestingly, the Luxury Bluetec models do not have the slotted rotors like the sport and 550's. Has anyone experienced this on a Luxury E350 with the solid/ventilated rotors?

 

The runout is the deposits melded onto the rotor. Iron rotors don't warp. Measured with a mic, there would appear to be high and low spots.

I didn't mean to insinuate you abused them, I think there is a cooling issue with the E series sport brakes, causing excessive heat.


From Zeckhausen Racing's site:

http://www.zeckhausen.com/technical.htm

http://www.centricparts.com/files/Ce...EV_3-15-11.pdf



Warped Rotors The term warped rotors is incorrectly used in most situations. The term is used most often to mean vibration
and roughness when the vehicle brakes are applied, but the cause is not a permanent distortion of the rotor
because one of the characteristics of the gray iron used in almost all rotors including racing is the high stiffness
quotient of the material called the Young’s Modulus. Instead the roughness that is observed is caused by a
previous unsuccessful machining of the rotor by a service provider or the non-uniform transfer of adherent pad
friction material. Once the deposit of pad material is present, a re-machining of the rotor surface appears to
solve the problem temporarily, seeming to confirm the idea that the rotor was warped. The problem is, if the
vibration existed for even a short time, that conversion of the iron below the deposit to cementite a iron-carbide
has occurred. Cementite is harder than the base iron matrix so when turned on a brake lathe, the harder
deposit area will deflect the nose radius on the cutting tool and the high spot will still be present to a degree
and the process of increasing deposit of new pad material over the high spot will re-start. Surface grinding of
the rotor will produce a suitable result if the two friction surfaces are flat and parallel but there will still be areas
of greater hardness. See “Adherent Friction” , “Brake Judder” and Transfer Layer”.

 

I'd get it in before 10,000 miles --- there has been talk of calling it normal brake wear and refusing warranty coverage. My service writer said I had 1,000 left before warranty denial when I was at 9,000. Others, and the manual, state 12,000. And get your car in before a year.

Now as to all this discussion about deposits, and statement that iron rotors don't warp, I don't know, but I'd sure like to hear that from a MB engineer. My brakes pulsed when I drove the car off the dealership with 10 miles on it. Now, that wasn't deposit!!!! Unless the factory found some way to overheat and ruin the brakes in 10 miles of test and delivery. And runout of .004 and .005 is a helluva "deposit."

I do know one thing, rotors can be machined badly, or installed badly, resulting in runout. And my rotors, front and rear, were way out of spec the day the car was delivered, per the dealers service invoice. (Dealer said, "Let it break in before we look at the brakes.")

BTW, my car is a 2011 E550 Luxury (not Sport). Perforated, NOT slotted rotors.

 

I recently had my front rotors & brakes replaced as well. 2011 550 with 8,000 miles on it. Service Manager said he hadn't heard of anything like this and did under warranty as special consideration. Pulsing was horrible at speed.

 

There is plenty of information out there about the warping myth, please do some research, call some mechanics, those that know will tell you about the hot spots. I do believe there is a design issue related to these brakes, too many have had issues at low mileage.

 

Is the pulsing coming from braking only or during driving as well?

 

wow wow wow..........
I have not had any issue's yet........hope I don't......

sorry to hear this, but at least it's an easy fix

 

Yes, the fix was easy to do, but costly if the dealer hadn't covered the parts and labor. Leith Mercedes of Raleigh has been my dealer of choice for 10 years. Their service department is always top notch. I highly recommend them to anyone in the Raleigh/Durham area.

 

Good advice!

 

In my case, from braking only. And very strong.

 

Same with my issue. It was not tire balancing or wheel runout.

 

So far I don't have a problem with the brakes. I have 5500 miles on them. Is this issue with drilled and slotted only/mostly? My 550 has cross drilled on the front. They are not slotted. The car has great stopping power. Down here I've had to try them out a few times with no hiccups.

 

You should be able to reduce brake problems and pad replacement if you use the paddle shifters for slowing at stop signs and lights...instead of the brakes. Hit the - shifter enough times to slow you down...then hold the + shifter until you back into automatic. Very easy to do.....you should at least double your brake pad life and reduce or eliminate rotor heating/warping.

 

Transmission wear will probably cost 3-4x the brake replacement though.

 

Yup,using too much paddle shifters sounds fun to me but in long term this will cost you more than brake pedal replacement

 

You folks with the pulsating brakes, did you also have excessive brake dusting on the wheels as well? I ask as it seems MB has changed the compound of the pads on recent models. Previously, wheels would be brown in a day, whereas, since I've had the E350 BT, over 4k miles, they stay clean, not much iron is hitting the wheels either (seen using Sonax wheel cleaner, it stays "green"). Just curious if the older pads did not absorb heat as well, causing the excess deposits on the rotors.