[nugent]

I have previously complained of vibration under braking at high (>50 mph) only.

Also a very weird, random jerk/clunk/grab a slow speeds or coasting. Not sure if the issues are related or not.

Anyway, finally pulled the front rotors. These pics are the left side. Plenty of wear still left.

No codes or warning lights at all.

 

[Kajtek1]

Those cars don't have sensors build into rotors,
Good thing you are still ok and able to type here.
What brand of rotors and pads?

 

[nugent]

R1 Concepts E-line rotors, Posi Quiet semi-metallic pads.

Also should mention that rears were recently replaced with Bosch Quietcast rotors and Pagid pads, which made no difference to the problems described.

 

[Kajtek1]

I think the semi-metallic pads are here to blame.
But I guess you have heavy foot as well? All rotors have sign of overheating.

 

[eurosport]

front rotors are warped - high speed braking can definitely do this - not sure if BAS would compound the problem - need to replace the front rotors and pads - no other cure

 

[nelbur]

Maybe it is just the photograph, but the inside side of the rotor looks black and the rust seems greasy. is that the case or is it just the way the photo was taken?

 

[nugent]

Just to be clear, all the photos are of the same rotor. Different angles and light to show up better. Not greasy, just pad dust and road grime.

This is my wife's car. She is an average driver - no heavy foot. I can't see how she would have overheated the rotors, unless the caliper stuck. Why would high-speed braking create a warp?

My research tells me that warped rotors are evident at low speeds. Her brakes have no vibration below 40 mph. I don't want to install new rotors and pads, only to find that nothing has changed.

Keep 'em coming!

 

[Kajtek1]

Easy test for warped rotors is turning them before removing the brake pads. Too late for that.
I don't think you have much choice here. Maybe this rotor is the source of vibration, maybe not, but that rotor does not qualify for reinstallation and machining of MB rotors is forbidden.

 

[Hirnbeiss]

How are the front wheel bearings, tie rod ens and ball joints?

 

[nugent]

Hirnbeiss, as far as I can tell everything is ok. Steering is good, no play pulling the wheel side-to-side, no vibrations when not braking. However, I have to say I am not an expert in this area.

 

[MBGraham]

front rotors are warped - high speed braking can definitely do this - not sure if BAS would compound the problem - need to replace the front rotors and pads - no other cure

Cars are equipped with ESP, but some posters seem to be too

How can you see those rotors are warped just from the pictures? They actually look like they have quite even wear.

Those grooves in the rotors are not normal, at least when OE or equivalent pads are used. You could check for run-out or warping. A cheap dial indicator with magnetic base from Harbor Freight would do it. Just put the magnetic mount on the caliper and the dial indicator point against the rotor, in a bit from the edge. I think runout is supposed to be under 2 thou. Mind you, those grooves look more than 2 thou, so you will need to find the best location. . If your bearings are cause, this would show that to0 because it measure the overall runout of bearings plus rotor.

One time, I had serious vibration on the E320, it was caused (with new disks and pads) by leaving car sitting for 3 weeks. The pads can apparently imprint the rotors where they were stopped. This changes the composition of the cast iron and causes uneven braking. I installed new rotors to fix that.

Only other thought, is to check the edges of the rotors. If corroded, perhaps pads catch on the edge at some speeds. Easy enough to grind or file the edge off if you have the disks off.

Finally, those discs and pads don't look too good. i would change them regardless. And that might solve the problem if you use OE quality parts.

 

[eurosport]

I managed to say the same thing in one sentence