Question about disk brakes post track day

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jackb_ms
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Question about disk brakes post track day

Hello All

I was checking my car post track day when I noticed some discoloration on my front disk brakes.

I cannot feel any lip on the brakes and there is plenty of "meat" on the pads.

Is this discoloration normal? 

Did I "cook" something?

Jack

 

SM25T
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That looks like you have worn a lot off the face of the disc, and you can see where each hollow is in the vented construction.
7 wonders of th...
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can just be the variation in material and the associated heat build up on the finned sections - normal

If your unsure about disc wear pop a micrometer over the disc and measure its thickness, the min thickness will be stamped on the edge to the disc should still be visable

7 wonders of th...
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Front vented discs 18mm new, 16.4mm min

SM25T
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I suspect that may be the problem
jackb_ms
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Thanks

I'll measure them later on this week.

What is the best / cost effective option to replaces the disk?

The pads have are barely worn, is it ok to re use them with new disk?

Jack

garybee
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Hard to tell from that picture, does the pad contact the disc right to the edge?  It isn't that unusual for that to be the case with aftermarket calipers and if so you won't get a lip.  It's easy to miss how much a disc has worn if that is the case.

SM25T
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You can use the pads with the new discs. Just go carefully at first while they bed in to the flatness of the new disc surface.
Doctor
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Those discs are ready for replacement. Probably flirting with minimal thickness with the discolorations over the "air" chambers where the thickness reduced. 

7 wonders of th...
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Igor,

Discolouration of that nature is normal after hard applications, once used normally this will disappear.

If worn below or very close to minimum, radially cracked or there's excessive variation then replacement is unnecessary.

Fine heat cracks in the surface are also common in high load applications

 

Regards reusing the pads, yes providing there's no contamination, uneven wear (wedge) or signs of delamination between friction material and backplate, they should be prepped by flatting them on 80 grit on a flat surface, sheet of glass for instance this abrades the surface, removes glaze and aids bedding in

Doctor
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Yes father. Still wouldn't want them on my car. Byebye