jopek

W211, 2009 E280 - Middle East

Could someone please comment on what these circular marks are on both my front disc rotors ?

These are original OEM factory discs which were skimmed by my local workshop at 41k kms and new Bosch pads fitted. The condition after skimming was maintained for about 10k km and the marks started to appear at about 50k km.

The car has now 61k km and these marks are getting more prominent as time goes by.

I am planning to replace everything with new rotors and pads but I'm wondering if there is any other underlying reason what both these disc should look like this.

I have seen many Mercedes cars here with similar circular pattern so its not just my car.

Thank you for comments.

PSDCampervan

It would appear to me that those slotted cooling rows are gradually carving grooves in brake pad material so that when they clamp down on rotor, contact pressure pattern of rotor becomes gradually more pronounced & uneven across clamping surface as friction removes rotor material (instead of pad material) in these areas resulting in hills & valleys across rotor clamping surface. I picture process to resemble a lathe cutting tool carving chips off a metal shaft as it spins in lathe's jaws. Maybe swap those out for some Zimmermann solid rotors (no slots) when time comes.

cmriv

heat glazed. replace pads and rotors.....