Black marks on brake discs

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greatnorthroad
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Black marks on brake discs

Post by greatnorthroad » Tue Mar 20, 2018 6:50 am

This might be one for the detailing section, but do you wise owls know the best way to remove black marks from brake discs? They are mainly black circles around the discs, and do not appear to be rusty. The car is a year old, with 8.5k miles and, unfortunately, is parked outside.

Thanks!
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Re: Black marks on brake discs

Post by scrounger » Tue Mar 20, 2018 8:38 am

greatnorthroad wrote:This might be one for the detailing section, but do you wise owls know the best way to remove black marks from brake discs? They are mainly black circles around the discs, and do not appear to be rusty. The car is a year old, with 8.5k miles and, unfortunately, is parked outside.

Thanks!

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Re: Black marks on brake discs

Post by greatnorthroad » Tue Mar 20, 2018 8:39 am

scrounger wrote:
Tue Mar 20, 2018 8:38 am
greatnorthroad wrote:This might be one for the detailing section, but do you wise owls know the best way to remove black marks from brake discs? They are mainly black circles around the discs, and do not appear to be rusty. The car is a year old, with 8.5k miles and, unfortunately, is parked outside.

Thanks!

Pictures if possible please
Can’t I’m afraid as I’m away this week.
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Re: Black marks on brake discs

Post by marco_polo » Tue Mar 20, 2018 8:42 am

Are they light scores?
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Re: Black marks on brake discs

Post by greatnorthroad » Tue Mar 20, 2018 8:45 am

marco_polo wrote:
Tue Mar 20, 2018 8:42 am
Are they light scores?
Yes. They don’t cause any judder or anything.
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Re: Black marks on brake discs

Post by marco_polo » Tue Mar 20, 2018 8:46 am

Not much you can do about those, but they might machine off in time.

I'd 'service' your brakes when you swap back to your summer wheels. All pads out, clean off all the dust and grit stuck in there.
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Re: Black marks on brake discs

Post by greatnorthroad » Tue Mar 20, 2018 8:51 am

marco_polo wrote:
Tue Mar 20, 2018 8:46 am
Not much you can do about those, but they might machine off in time.

I'd 'service' your brakes when you swap back to your summer wheels. All pads out, clean off all the dust and grit stuck in there.
Yes, was planning to give them a good clean when I swap wheels. I’ve never removed pads myself though, so might have to miss that step.

I’ve read about people using steel wool and degreaser on the discs. Any thoughts on that - safe, sensible, effective?
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Re: Black marks on brake discs

Post by marco_polo » Tue Mar 20, 2018 8:55 am

It couldn't be easier to remove/replace the pads on ours luckily, they're nothing like as complicated or clunky as 95% of the cars on the road.

Don't mess with the brake disc's friction surface though.
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Re: Black marks on brake discs

Post by greatnorthroad » Tue Mar 20, 2018 8:58 am

marco_polo wrote:
Tue Mar 20, 2018 8:55 am
It couldn't be easier to remove/replace the pads on ours luckily, they're nothing like as complicated or clunky as 95% of the cars on the road.

Don't mess with the brake disc's friction surface though.
Okay - noted thanks. Are there any idiot’s guides out there on how to remove the pads?
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Re: Black marks on brake discs

Post by marco_polo » Tue Mar 20, 2018 8:59 am

This guy makes a bit of a meal of it, it genuinely shouldn't take as long as 2 minutes.

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Re: Black marks on brake discs

Post by Blind Pugh » Tue Mar 20, 2018 9:00 am

greatnorthroad wrote:
Tue Mar 20, 2018 8:51 am
marco_polo wrote:
Tue Mar 20, 2018 8:46 am
Not much you can do about those, but they might machine off in time.

I'd 'service' your brakes when you swap back to your summer wheels. All pads out, clean off all the dust and grit stuck in there.
Yes, was planning to give them a good clean when I swap wheels. I’ve never removed pads myself though, so might have to miss that step.

I’ve read about people using steel wool and degreaser on the discs. Any thoughts on that - safe, sensible, effective?
Based on my 1st hand experience - suggest you invest in a FlexHone on a handdrill - <5mins each disc with one of these....

ImageImage

.....evens out existing disc surface area.

https://www.pacehigh.co.uk/flex-hone-for-rotors.
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Re: Black marks on brake discs

Post by greatnorthroad » Tue Mar 20, 2018 9:06 am

marco_polo wrote:
Tue Mar 20, 2018 8:59 am
This guy makes a bit of a meal of it, it genuinely shouldn't take as long as 2 minutes.

Ok great thanks.
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Re: Black marks on brake discs

Post by greatnorthroad » Tue Mar 20, 2018 9:07 am

Blind Pugh wrote:
Tue Mar 20, 2018 9:00 am
greatnorthroad wrote:
Tue Mar 20, 2018 8:51 am
marco_polo wrote:
Tue Mar 20, 2018 8:46 am
Not much you can do about those, but they might machine off in time.

I'd 'service' your brakes when you swap back to your summer wheels. All pads out, clean off all the dust and grit stuck in there.
Yes, was planning to give them a good clean when I swap wheels. I’ve never removed pads myself though, so might have to miss that step.

I’ve read about people using steel wool and degreaser on the discs. Any thoughts on that - safe, sensible, effective?
Based on my 1st hand experience - suggest you invest in a FlexHone on a handdrill - <5mins each disc with one of these....

ImageImage

.....evens out existing disc surface area.

https://www.pacehigh.co.uk/flex-hone-for-rotors.
Like this one: https://www.amazon.co.uk/gp/aw/d/B00K38 ... ref=plSrch ?
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Re: Black marks on brake discs

Post by marco_polo » Tue Mar 20, 2018 9:10 am

We used to use something very similar in Kawasaki on the hydraulic motor valve-covers, it was all CNC controlled by the lathes though.

Can you imagine if some numpty didn't hone them perfectly evenly due to a stubborn spot (or whatever?! Chunk-a-chunk-a-chunk down the road! :lol:
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Re: Black marks on brake discs

Post by greatnorthroad » Tue Mar 20, 2018 9:15 am

marco_polo wrote:
Tue Mar 20, 2018 9:10 am
We used to use something very similar in Kawasaki on the hydraulic motor valve-covers, it was all CNC controlled by the lathes though.

Can you imagine if some numpty didn't hone them perfectly evenly due to a stubborn spot (or whatever?! Chunk-a-chunk-a-chunk down the road! :lol:
Mmm, indeed. Some numpty like yours truly :roll:
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