I have used EC high Temp Epoxy with pigment as a paint for brake calipers -- they lasted less than a year before starting to peel off... this was on a bike, that was occasionally used as a trackday tool ..
(Had some EC High temp and pigment, and was too cheap to go buy the "caliper paint" available

)
On a normal road car, i would expect that the high temp would last much longer, since they will see much less UV and not go above 180 degrees C for longer periods (unless your brake pads hang

)
Give it a go, and post pictures ..
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