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Interesting marks on brake discs

Chassis/Brakes/Steering/Wheels discussion
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Interesting marks on brake discs

Post by Sailor » Wed Apr 29, 2015 6:44 pm

The front brakes on our Lude judder, if only slightly and occasionally. The discs feel a lot smoother than they look in these pictures, and have enough meat on them; and there's plenty of pad left.
However, I did notice some radial markings. They're not scratches or cracks - in fact, you can't feel them even though you can see them.

Any ideas?

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Re: Interesting marks on brake discs

Post by Doggo » Wed Apr 29, 2015 7:00 pm

I don't know. Sometimes I feel like jacking it all in, moving to Peru and farming llamas.

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Re: Interesting marks on brake discs

Post by Doggo » Wed Apr 29, 2015 7:01 pm

But if you mean the discs, the marks might have been put there by a very small and slightly stupid alien intelligence?

Just a thought. I'm not saying it's right.

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Re: Interesting marks on brake discs

Post by Doggo » Wed Apr 29, 2015 7:04 pm

Maybe a manufacturing Quirk? A ridge from when they were forged or cast, which though machined off is in the grain of the metal and is showing through?

Edit: Good luck with it anyway.
Last edited by Doggo on Wed Apr 29, 2015 9:13 pm, edited 1 time in total.

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Post by vetrox » Wed Apr 29, 2015 7:09 pm

The first pic just looks like the remnants of a brake that seized on. If it judders then the discs are warped and need replacing :-(

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Post by ek9sid » Wed Apr 29, 2015 7:31 pm

I've seen this plenty of times. Always put it down to residue from the brake pads

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Post by wurlycorner » Wed Apr 29, 2015 7:33 pm

Yep, normally residue from the edge of where the pad friction material has been sat after you've parked up with the brakes really hot.
Those particular marks should disappear after a short time (though you might get others that replace them :lol: )
If not, it does suggest a manufacturing problem in the disc.

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Post by RattyMcClelland » Wed Apr 29, 2015 7:46 pm

Discs don't warp. People just seem to diagnose that as an issue for reasons I can't understand.
It's uneven pad material distribution.
That looks like pad material for hot braking and holding the brakes at a standstill for extended periods of time like traffic lights.
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Post by Sailor » Wed Apr 29, 2015 11:54 pm

Food for thought. Thanks.

I don't recall getting the brakes particularly hot and I always use my handbrake at traffic lights.
However, a couple of replies on the ATR forum agree with the pad material theory. One respondent even provided a useful link: http://www.essexparts.com/learning-cent ... ost/Bed-in

Perhaps I should try a bit of emery paper?
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Post by Doggo » Thu Apr 30, 2015 7:08 am

I agree that nail care is important, but you really ought to focus on the problem.

Sorry. I'll shut up now.
Again, hope you get her sorted relatively cheaply.

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