23-09-24, 08:53 AM
(22-09-24, 09:07 PM)agricola Wrote: Discounting chemical reaction, water marks etc, I'm leaning towards hairline cracks at the surface. Reason I say that is because the rotor looks to have its fair share of wear judging by the steps at the outer and inner edges, with the deepest scores across the affected holes. As rotors wear, the characteristics of the metal can subtly alter due to constant heating/cooling/chemicals on the road etc and this can show up on the surface as hairline cracks a few microns deep. I'd check the rotor thickness against the minimum spec first and if on the limit or below, then new rotors first up
i cant see any hairline cracks not without checking with a magnifying glass ,which now i will check deeper as i do have a magnifying glass but i did search online about this very topic you suggest and the hairline cracks are very visible to the naked eye but they might have been extreme examples ? , but it could be that these marks are the precursor to hairline cracks ? you are correct , the discs are fairly worn and are near the wear limit, i dont know what mileage you'd expect to get out of discs but id imagine way more than the 32 k its done .