ITS 24 disc brakes - Black marks & deposit on 4 discs

[Ayzoterik]

Since a couple of days I've noticed a black deposit on my 4 disc brakes and I'm not sure what could have caused this.

My discs are all stained with some pads marks in certain spots and black deposits.
I live in Quebec and we had cold temperature in the past weeks like -20 Celsius.
I was wondering maybe the brake fluid didn't like the cold weather ?

It also left some deposits on my mags, not sure if it's fluid or brake pads deteriorating.
It's too cold here to have a thorough checkup, I'll need to bring the car to the dealer anyways for the steering gearbox recall, but I wanted your opinion on this first.

If anyone experienced the same issue or have any clue of what could have caused this, I'd appreciate any input.

Thank you!

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[creaturemachine]

Looks to me like they're just dirty. Those pads leave a lot of dust that just builds up in weather like this.

 

[Victorofhavoc]

The factory pads are okay for their grab in the very cold, but they do give up pad life/dust to achieve it. It's hard for them to warm up in winter conditions. They'll build up like this on most cars with "performance brake pads", but you can gently bed them to clean them up and reduce eventual judder. Alternatively a red sanding pad made for metal works well to clean them up if you prefer to do it by hand.

It builds up a bit less if you're more gentle on the brakes for the first few miles. Whenever abs activates in super slick/cold it's beating up the pads, especially when you've just set off and they're cold and brittle.

 

[Ayzoterik]

Looks to me like they're just dirty. Those pads leave a lot of dust that just builds up in weather like this.

Oh, good to know, and reassuring.
Ty !

 

[Ayzoterik]

The factory pads are okay for their grab in the very cold, but they do give up pad life/dust to achieve it. It's hard for them to warm up in winter conditions. They'll build up like this on most cars with "performance brake pads", but you can gently bed them to clean them up and reduce eventual judder. Alternatively a red sanding pad made for metal works well to clean them up if you prefer to do it by hand.

It builds up a bit less if you're more gentle on the brakes for the first few miles. Whenever abs activates in super slick/cold it's beating up the pads, especially when you've just set off and they're cold and brittle.

I didn't know that. Thought the brake pads were made from the same composite as the others.

I'm usually very progressive and gentle on breaking, but I can remember a time this winter where I had a little more spirited run.

Thanks for your tips Victor ! I'll definitely try to go easy on them for the remaining of winter and bed them gently to clean them until spring comes.

 

[Victorofhavoc]

I didn't know that. Thought the brake pads were made from the same composite as the others.

I'm usually very progressive and gentle on breaking, but I can remember a time this winter where I had a little more spirited run.

Thanks for your tips Victor ! I'll definitely try to go easy on them for the remaining of winter and bed them gently to clean them until spring comes.

They're the brembo performance pad in front, and someone confirmed recently the ate compound in back. Brembo also has a ceramic performance pad that doesn't bite as well as the semi pad, but won't deposit as much.

It's more a visual problem than anything, but if the deposits get really bad then it can cause judder once the brakes get very, very hot.

You can romp on them once they're warm, but yeah they just take longer in winter. The air deflectors and venting in front help for track use, but they hurt in winter . Trade offs!

 

[Ayzoterik]

They're the brembo performance pad in front, and someone confirmed recently the ate compound in back. Brembo also has a ceramic performance pad that doesn't bite as well as the semi pad, but won't deposit as much.

It's more a visual problem than anything, but if the deposits get really bad then it can cause judder once the brakes get very, very hot.

You can romp on them once they're warm, but yeah they just take longer in winter. The air deflectors and venting in front help for track use, but they hurt in winter . Trade offs!

Wow. Some stuff I should have known from the start. Until now, the car performed very well in winter and it's still doing fine, but if it means they'll break down during winter, I might look for another brand of semi pads at least to compare or give the ceramic a try probably.

Only that compound residual that made me think something was wrong and yeah, it looks dirty. 🫣

 

[Victorofhavoc]

Wow. Some stuff I should have known from the start. Until now, the car performed very well in winter and it's still doing fine, but if it means they'll break down during winter, I might look for another brand of semi pads at least to compare or give the ceramic a try probably.

Only that compound residual that made me think something was wrong and yeah, it looks dirty. 🫣

Google around for "brake pad imprinting" and you'll start getting an idea of this phenomenon.

Ime, It's just more common with higher performance pads that dust more. Winter definitely makes it worse. Rebedding or scrubbing helps in spring.

 

[Ayzoterik]

Google around for "brake pad imprinting" and you'll start getting an idea of this phenomenon.

Ime, It's just more common with higher performance pads that dust more. Winter definitely makes it worse. Rebedding or scrubbing helps in spring.

Will definitely do my research.

When springs comes, I'll clean to whole caliper and try to give the pads a good scrub.

What do you think I should use for that, like a brush wire or even sandpaper maybe

 

[Victorofhavoc]

Will definitely do my research.

When springs comes, I'll clean to whole caliper and try to give the pads a good scrub.

What do you think I should use for that, like a brush wire or even sandpaper maybe

I typically buy the "red metal sanding pad" at Ace or home depot. They're abrasive enough to scrub the surface, but not so abrasive to damage the rotor. Definitely don't use it on the caliper unless you want to strip the paint off. Brake kleen helps get some of the gunk off and to loosen it for the red pad. Wear gloves and possibly a respirator when using corrosive chemicals like brake kleen. It's safe on your caliper paint. I use brake kleen with a cotton Terry cloth to clean off calipers, arms, and most things in the wheel well every spring. Once cleaned off I pull the car out and wash it well, then detail wheels, paint, re-up ceramic and such as part of my spring routine.

You can pull the pads off and check that they haven't cracked or aren't chunking. I've seen that happen a few times in my area (very cold and icy winters) where people will engage abs from cold stop all the time and eventually the pads crack and deteriorate. As long as they look like one nice piece of pad, they should be totally fine. My pads seem okay and today we have -6F static temp and -15 wind chill. They definitely take way longer to stop until they warm up. They are definitely dusting more than when it's warm out. I get some imprinting from the rear pads, but that's more due to it being damp/frozen out and the electronic parking brake squeezing so hard. If I had a manual brake, I'd only pull it halfway unless I was on a hill, and in my garage or after the pads have gotten super hot, I'd never pull the brake. Epb makes that a bit more challenging. Ce la vie

 

[Ayzoterik]

I typically buy the "red metal sanding pad" at Ace or home depot. They're abrasive enough to scrub the surface, but not so abrasive to damage the rotor. Definitely don't use it on the caliper unless you want to strip the paint off. Brake kleen helps get some of the gunk off and to loosen it for the red pad. Wear gloves and possibly a respirator when using corrosive chemicals like brake kleen. It's safe on your caliper paint. I use brake kleen with a cotton Terry cloth to clean off calipers, arms, and most things in the wheel well every spring. Once cleaned off I pull the car out and wash it well, then detail wheels, paint, re-up ceramic and such as part of my spring routine.

You can pull the pads off and check that they haven't cracked or aren't chunking. I've seen that happen a few times in my area (very cold and icy winters) where people will engage abs from cold stop all the time and eventually the pads crack and deteriorate. As long as they look like one nice piece of pad, they should be totally fine. My pads seem okay and today we have -6F static temp and -15 wind chill. They definitely take way longer to stop until they warm up. They are definitely dusting more than when it's warm out. I get some imprinting from the rear pads, but that's more due to it being damp/frozen out and the electronic parking brake squeezing so hard. If I had a manual brake, I'd only pull it halfway unless I was on a hill, and in my garage or after the pads have gotten super hot, I'd never pull the brake. Epb makes that a bit more challenging. Ce la vie

Red metal sanding pad eh, I'll give it a try.

I have brake cleaner, yeah will def protect myself, ty !
Man, that's an interesting routine to implement myself every springs.

I miss the good old handbrake.
Thanks for the tips ! Will keep you good advises in mind once springs hit.
These performance cars... they're keeping us busy I see, c'est la vie !

 

[creaturemachine]

Try an iron remover like https://www.autoglym.com/magma.html

au printemps, bien sur

 

[Ayzoterik]

Try an iron remover like https://www.autoglym.com/magma.html

au printemps, bien sur

Interesting product, made in Great-Britain

Will definitely use this on wheels and calipers I guess.

Thanks again Victor !

 

[boosted_canoe]

try doing several consecutive hard stops. you want to get them hot. this will help burn off the deposits.

 

[Ayzoterik]

Interesting product, made in Great-Britain

Will definitely use this on wheels and calipers I guess.

Thanks again Victor !

Oops. CreatureMachine I meant. Sry buddy

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