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I drove about 500km yesterday in very slushy/wet snow. Today I noticed my left rear rotor has 2 thin bands of rust that will no go away. Should I be having the dealership take a look or will this eventually resolve on its own? I tried pressure washing the caliper/break pad thinking that there might be a couple small pebbles that are stuck. Unfortunately, this did not improve anything. I have attached images below for reference. Rear Left: note the two thin bands of rust Rear right: no thin bands of rust
Worth asking about - likely the pad is for whatever reason lacking a bit of material in that area. Both rotors show a similar process at work. The caliper holders may be jamming a little, perhaps need a de-rusting and lube.
You want to see REALLY bad rust rings?
My son-in-law's Equinox V6. Front rotors! The caliper holder was so corroded that the pads could not move properly and it wore the inner pad out prematurely. Our cleaning the rust off and a light lube made the replacements work like new.
The pads should be removed and inspected to find the source of the problem. Best case, a foreign object is found and can be removed and you'll be back in business. Pads are completely capable of rubbing away mild rust. If the pads are damaged on the other hand they will need to be replaced. The dealer may jump at the chance to tell you all the pads and rotors on the car should be replaced, I advise some skepticism. You might get a second opinion from an independent Mercedes mechanic.
One other note - it's generally not a good idea to use a pressure washer on your brakes, as there are rubber seals that could be breached, causing corrosion and premature failure. This would require a brake caliper rebuild.
I drove about 500km yesterday in very slushy/wet snow. Today I noticed my left rear rotor has 2 thin bands of rust that will no go away. Should I be having the dealership take a look or will this eventually resolve on its own? I tried pressure washing the caliper/break pad thinking that there might be a couple small pebbles that are stuck. Unfortunately, this did not improve anything. I have attached images below for reference. Rear Left: note the two thin bands of rust Rear right: no thin bands of rust
go try to re-bed the brakes. This did not just happen but became evident with salt. You could remove the pads to look for a You could remove the pads to look for a pebble first because the pressure washer is not gonna get that out. Otherwise, new pads, and rotors with a proper bedding in.
I have my first Service A coming up in 1600 km. Would these brake pads/rotors be covered under warranty given the vehicle is less than a year old? I'm not sure if its related or not, but my left rear brake in the summer woud occasionally make a squeeking noise when braking slowly (ex. while in a drivethrough).
Good to know about not pressure washing the calipers. I'll make sure not to do that again. Hopefully I didnt cause any damage doing that. I was hoping that I could try and rinse off any debris that might have been between the pad and rotor.
I have my first Service A coming up in 1600 km. Would these brake pads/rotors be covered under warranty given the vehicle is less than a year old? I'm not sure if its related or not, but my left rear brake in the summer woud occasionally make a squeeking noise when braking slowly (ex. while in a drivethrough).
Good to know about not pressure washing the calipers. I'll make sure not to do that again. Hopefully I didnt cause any damage doing that. I was hoping that I could try and rinse off any debris that might have been between the pad and rotor.
parts that are listed wear and tear (and who’s wear and tear could be influenced differently by different users) are not covered by warranties and are listed in the manual. It will be your job to explain why this is a manufacturers defect which for most parts is an easy conversation because they should last 50,000 miles. The manufacturer knows brake pads and rotors could be burned out in 20,000 miles, or tires could be burned out in 10 or 15,000 miles so that’s not a gamble they take in covering because they have no idea of the life of those parts for each individual user. If when the brake pad is taken out, they find a pebble in there, that’s not a manufacturer warranty. That’s standard maintenance. Not sure exactly the type of products they put on your roads, but in many areas they mix salt with slag, and that stuff tends to wind up in the brake rotors.. so if that rotor rust ring is indented, it’s from a pebble. If that rust ring sits proud, you might be able to ask why your brake pad failed.. but if they find that the brake pad was eaten by something stuck to the rotor, that’s a maintenance issue. Personally I like to know exactly what the problem is so I know how to argue whether or not it would be covered, or whether the approach is to go slather the dealer in honey 🍯 and see if they can do a favor for you.. so take out that brake pad and see what type of argument you can legitimately win.
Last edited by Baltistyle; Jan 7, 2026 at 06:08 AM.
My guess, a couple of pebbles were dragged across the brake pad forming grooves in the pad which now does not contact the disc and without that contact rust rings formed. Not a manufacturing defect and so not a warranty situation. Probably will work its way out as pad wears down. I would not spend a penny on this. My two cents.
I speak from experience when I say that they should be covered with no question.
In 2008 the rear rotors on our then new B200 were rusting and all 4 were changed under warranty. I thought the front ones were fine (they were mildly warped, a chronic problem with that car).
I speak from experience when I say that they should be covered with no question.
In 2008 the rear rotors on our then new B200 were rusting and all 4 were changed under warranty. I thought the front ones were fine (they were mildly warped, a chronic problem with that car).
You speak from your experience with a different problem. Goodwill also is not a warranty. I speak from driving in Northern Maine winters for years and constantly dealing with this exact type of ring on the rotor, but hey, lets not throw anything on the table, and help op understand the written limits of the warranty
Same problem; the solution was described to me at the time as a warranty repair but if it was a goodwill effort, it made no difference to the end user, who was satisfied. Here's hoping that will happen for the original poster as well.
those rust rings are just road salt and grime preventing the pads from scrubbing the rotor surface find a safe road and do 5 firm stops from 60kmh to 10kmh to burn them off only go to the dealer if you hear metal scraping or feel the pedal pulsating
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