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Discussion Starter · #1 ·
Hello everyone. Recently changed the whole braking system (discs and pads) to the OE Brembo in my CLA 45 AMG (2017).

I attach two images.

1. Why this happens when my car stays for 2-3 days without driving? I have never had such thing before with previous cars. It happened exactly the same with the previous breaks on my CLA, but I thought that it will go away if I change them...

67242


2. After driving a while (15-20 km) MOST of the rust is gone. BUT... Look at this picture.

How to get rid of this strange rust in A/B/C spots??? Should I worry about it? It's the new braking system, can someone explain me wtf?

67243
 

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Rain or heavy fog lately?

You say Brembo rotors? With the so called “coating” ?
 

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This is normal, I have big drilled rotors on my CLA as well. Whenever it's wet or damp, they will have a thin coating of rust. As soon as you brake from say 40km/h, that rust layer will immediately disappear
 

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Discussion Starter · #4 ·
Hey all. Thanks for the answers.

Maybe not heavy rain, but yep. It rained. But honestly I've never had such thing in any previous of my normal (without holes etc.) brakes in other cars.

After 15-20 km drive I took the second picture I posted. And as you can see, the disc is clear, but the rust is in area marked as "A". I'm most afraid of that. Because there is no traction, so how do I remove this rust here...? :(
And it's in the holes (mark B), but I think it came from the disc.
And very strange - C area. It's simmilar to A. There is no traction, so how do I remove this? Any idea? Or need to worry?


@jmc, yes exactly. With coating. Those are the ones I have (front and rear). Should I add pads too? I can search for them.

 

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Should not get rust on coated surfaces ... the whole point of the coating right?

Mine are more than 7 years old ... the grey coated segments have no rust
 

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....It happened exactly the same with the previous breaks on my CLA, but I thought that it will go away if I change them...
a) What city are you near?
b) Any bodies of salt water around your driving routes?
c) Do your friends / neighbors have this same problem?
 

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Yeah, the rust shouldn't be there, generally... but rotors are made of iron and other alloys... I have had other cars where the brakes would always be rusted after allowing it to sit around... and some cars the brakes is always good. Depends on the quality of the alloys used in the rotors. But it should not impact performance... Just get it replaced by dealer if they cover the warranty, and if not just go buy a good one from online, Zimmermann makes good rotors.
 

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Hey all. Thanks for the answers.

Maybe not heavy rain, but yep. It rained. But honestly I've never had such thing in any previous of my normal (without holes etc.) brakes in other cars.

After 15-20 km drive I took the second picture I posted. And as you can see, the disc is clear, but the rust is in area marked as "A". I'm most afraid of that. Because there is no traction, so how do I remove this rust here...? :(
And it's in the holes (mark B), but I think it came from the disc.
And very strange - C area. It's simmilar to A. There is no traction, so how do I remove this? Any idea? Or need to worry?


@jmc, yes exactly. With coating. Those are the ones I have (front and rear). Should I add pads too? I can search for them.

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Mine does exactly the same, the worse thing you can do is wash the car and park it afterwards, make sure you either blow the brakes dry or go for a short drive to remove any water. Otherwise they may seize with rust and I couldn't release them by trying to move the car. In the end I have to apply brake cleaner on them and the put it in reverse again, until it broke free.
 

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Hello everyone. Recently changed the whole braking system (discs and pads) to the OE Brembo in my CLA 45 AMG (2017).

I attach two images.

1. Why this happens when my car stays for 2-3 days without driving? I have never had such thing before with previous cars. It happened exactly the same with the previous breaks on my CLA, but I thought that it will go away if I change them...

View attachment 67242

2. After driving a while (15-20 km) MOST of the rust is gone. BUT... Look at this picture.

How to get rid of this strange rust in A/B/C spots??? Should I worry about it? It's the new braking system, can someone explain me wtf?

View attachment 67243
okay, one other thing, if you look at the pics you posted, the parts of the brakes that continued to rust are areas where it is not touched by the pads during the braking. I think this is all to be expected. I really think you are making a mountain out of a mole hill. Maybe move to California or colorado , hot dry weather during the summer.

Salt and contaminants in the water will easily cause rust in the brake rotors. no two ways around it... fact of life...


and I realize this "newposter" has stopped posting... i think he/she just wanted to rant the frustration of not having the perfect ideal rotors that never rust...
 

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now now be nice

actually new guys has a point ... the coated but noncontact segments should not be rusting as thats the whole point of the coat

though i do recall others noting the brembo fancy uv gibberish doesnt hold up ... as seen here

i am not even sure if the zimms silver coat will hold ... the oem grey stuff seems much tougher
 

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now now be nice

actually new guys has a point ... the coated but noncontact segments should not be rusting as thats the whole point of the coat

though i do recall others noting the brembo fancy uv gibberish doesnt hold up ... as seen here

i am not even sure if the zimms silver coat will hold ... the oem grey stuff seems much tougher
Okay I will be nice... :giggle:

My Raybestos rotors is holding up well, no rust , even for our Vancouver rainy weather.

Maybe he just got a bad lot of Brembo rotors... production quality issues...
 

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IMO the amount of rust is perfectly normal. Except for a part of the hub, the rotors are not coated with anything because doing so will reduce cooling effectiveness. It's normal for rotors to rust as shown in the original post. The part of the rotor hub that is rusting is the part that faces the wheel - this part of the rotor is also not coated because it contacts the wheel. If you want to, you can carefully coat this exposed part of the hub with some grey paint made for painting calipers. Just be careful not to get any paint onto the part that the wheel comes in contact with because it will prevent the wheel from sitting perfectly flush.
 

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My oem rotors look to have the coat throughout ... right through the cooling vanes

The thermal plume from a moving rotor with the particular turbulent displacement pattern inside will do most of the convect work presuming a nice even thin antirust coat which it is

My rims never get hot which means the rotor dissipation is pretty good ... even after a downhill run of -3500ft (just did that recently)

Though yes lather on an uneven thick layer of paint on the hat and vanes then the paint will have to boil or peel off before proper cooling starts
 

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Discussion Starter · #14 ·
and I realize this "newposter" has stopped posting... i think he/she just wanted to rant the frustration of not having the perfect ideal rotors that never rust...
Nah, a lot of work recently. Sorry for the delay ;)

Then cool guys, thanks for the answers. Now I'm less concerned about it.

Any recommendation how to clean the "C" marked area of the rotor? I know one of you suggested to get it painted, but those rotos are almost completely new so I guess the rust should come off easily.
 

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Nah, a lot of work recently. Sorry for the delay ;)

Then cool guys, thanks for the answers. Now I'm less concerned about it.

Any recommendation how to clean the "C" marked area of the rotor? I know one of you suggested to get it painted, but those rotos are almost completely new so I guess the rust should come off easily.
Honestly , I would not fret over it. Even after you cleaned it , the rust will come back again.
And to paint it , means you have to pull the rotors and paint coat the vanes and the drilled holes. Not that easy.
not sure it’s worth the cost and time to do it.
I have had rotors which rusts every time I drove it in rainy or wet weather, but no real performance issues except for the early morning squeak when first driving it.
 

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... or a long s s c c r r a a a a a p p e e ...

almost as bad as fingernails on a chalkboard
 

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a) What city are you near?
b) Any bodies of salt water around your driving routes?
c) Do your friends / neighbors have this same problem?
@NewUser > Can you update us on Comment #6?
 
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