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Ask Lou P. master tech Your Own Question
Lou P. master tech
Lou P. master tech, Mercedes Technician
Category: Mercedes
Satisfied Customers: 4087
Experience:  15 years master certified 100% fix rate and have access to factory radio codes, wiring, and instructions.
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I just picked up my E550 2013 coupe from Mercedes service.

Customer Question

I just picked up my E550 2013 coupe from Mercedes service.
Vin WDDKJ7DB5DF197153
Mileage. 27836
They just installed the 3rd set of rear rotors. This set only had 3700 miles on them, most of which were highway. One of brake pads had a chunk about the size of a dime missing off the edge but otherwise looked excellent. After leaving the dealership,getting on the interstate, the same vibration was still there. Can hear and feel in seat. Absolutely no vibration feel or visual shake in steering wheel. Am now told my front rotors are the cause and need replaced to the tune of $600. I ask them to mic the fronts and was told they can not mic them because they are cross drilled. Why can Porsche mic their rotors and not Mercedes?
I have never replaced front rotors with only 28000 miles of primarily interstate driving.
Please help me understand this problem. I drive my E a 2014 ML and a roadster. Never had this much frustration😡
Steve Atkinson (###) ###-####
Service by University Motors Mercedes Benz. Morgantown WV
Submitted: 10 months ago.
Category: Mercedes
Expert:  Lou P. master tech replied 10 months ago.

Hello Steve. i am going over your story now to see how i can be of assistance,. i will reply back asap , Lou P.

Expert:  Lou P. master tech replied 10 months ago.

ok first off, let me ask, does the vibration get worse when pressing the brakes or not? is the vibration felt in the brake pedal?

Expert:  Lou P. master tech replied 10 months ago.

As for micing the rotors, you can use a micrometer to read the thickness but because of the holes you cannot use a dial indicator to check for runout.

Customer: replied 10 months ago.
I only get the vibration when braking. The vibration stays consistent with pressure on pedal. Does not get worse with added pressure
Customer: replied 10 months ago.
Keep in mind! 3 sets of rear rotors in 28000 miles. Problem someware?..
Expert:  Lou P. master tech replied 10 months ago.

understood

Expert:  Lou P. master tech replied 10 months ago.

3 sets of rotors tells me the issues is not with the rotors, at least in the rear

Expert:  Lou P. master tech replied 10 months ago.

heres my thinking, and from my own experience

Customer: replied 10 months ago.
What are your thoughts as nothing came through
Expert:  Lou P. master tech replied 10 months ago.

when rotors become warped it is due to excessive heat, the reason the heat gets excessive is because something in the system is not doing its job, so when the rear rotors warp it is because the fronts are not doing their job and vice versa, also most people just slap rotors on the wheel hub, what actually needs to be done is the face of the hub needs to be cleaned with a wire wheel. you cannot place a flat rotors mounting surface against a rusted hub, and they all rust. also has anyone checked the rims for bends? if a wheel got bent then the wheel bearing and hub will bend so even if you change the rotors you will still have excessive runout due to the bend in the affected hub, sometimes you can simply raise the car in the air and spin the wheel by hand, if you hear a non consistent , chh, chh, chh then the rotors or hub bearings are warped/bent.

it sounds like they are not accurately diagnosing this (obviously ) they are simply throwing parts at it.

Expert:  Lou P. master tech replied 10 months ago.

i was typing :)

Expert:  Lou P. master tech replied 10 months ago.

the best test for me and rotors is to get up to about 70mph and lay on the brakes about 3-4 times and let them get good and warm and then it will be obvious if the shake is in the front or rear.

Expert:  Lou P. master tech replied 10 months ago.

what are your thoughts on my response.

Customer: replied 10 months ago.
I am leaving for the highway now. Will write when I finish hard braking 😎
Expert:  Lou P. master tech replied 10 months ago.

ok (thumbs up)