I generally keep track of this stuff for my own reference, but figured someone else might find it interesting at some point.

I am in the middle of a brake job on my 91 Formula due to a blocked front hose. In this case it froze with the caliper clamped, and smoked the right front brake... Anyway, I noticed a few markings while cleaning up the calipers. I'm reasonably certain the calipers are original equipment.

On the top of the caliper, there's a pink paint dab on the top corner forward of the piston. There's also a white scribble around the opening. On the bottom of the caliper, each has an orange paint dab approximately in-line with the middle of the piston. All of these marks were under layers of brake dust and dirt. They barely show up in photos, but they're definitely there.

 

Looks like they had a black coating from the factory as well. I never knew that.

 

Have to admit, I did not notice marks on the calipers before . . but I did see markings on the rotor hat . . .

 

I'm guessing the only reason these marks survived to be seen, is that I ran out of brake cleaner and was cleaning the calipers in the sink with warm water, Dawn, and an old toothbrush. The photos I posted were taken shortly after giving the calipers a blast of brake cleaner before a squirt of fresh black paint, the marks were more definitely more visible before the brake cleaner. Had I started with a solvent, they may have rinsed away completely without being seen.