Just received some Brembo discs. Was just about to clean one and install when I noticed one had what looks like a scratch on it. I am sending back to retailer. They will accept return but claim it's just a surface scratch and it's ok. Is it ok? Also, do the discs look brand new to you?

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  • That looks like a crack to me, not a scratch. It suddenly changes direction through 90 degrees at the top. Scratches don't usually do that. The whole surface finish looks odd, but it doesn't look like the rotor has actually been used. And what is the black grainy-looking stuff supposed to be? – alephzero Mar 5 '19 at 14:16
  • I was suspicious about the black grainy stuff. It made me wonder if the disc had been installed for a very short period of time and had picked up some friction material from the pads. Then again, it could just be the appearance these discs have from new. – PeteUK Mar 5 '19 at 14:25
  • 2
    The overall look is brand new to me ... however, I WOULD NOT let the crack slide. I'd get a replacement for the rotor as the crack will only get bigger with heat cycles. You will know for sure if it's a crack if since it goes down to the edge of the rotor, is the crack also seen in the edge of the rotor? If it is, take some bright red Sharpie and circle the affected area before you send it back to the retailer. Also, just because you cannot see it in the end does not mean it isn't a crack. Still circle the entire thing. You don't want that disk in circulation. – Pᴀᴜʟsᴛᴇʀ2 Mar 5 '19 at 14:40
  • It's hard to tell if it is a crack from the angle, I'd want to see whether the mark goes down the edge – GdD Mar 5 '19 at 16:06
  • It is a crack; I would want a Magneflux or equal test to check if the other rotor(s) are cracked. When one is defective it implies the manufacturing process is not controlled. – blacksmith37 Mar 5 '19 at 16:35

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