Overheated Rotors

[nghtshd88]

My rear rotors in particular are pitch black besides needing to be changed only after a few thousand miles since the last cut. And thats driving very conservative. When I last chabged them it was very hard to turn the pistons back in. I cant see how they actucally can retract on their own. They arent actually dragging as I can still turn the wheel freely or smoking but I guess its enough still.

Just curious if anyone else has similar issues at this point in time? My 04 had the same issues. Im looking at getting new calipers this time around.

 

[TooManyToys]

The normal piston rollback after pressure release is only thousands of an inch. Retraction of the parking brake mechanism is a different related item, but an intregal parking brake design makes it hard to perceive freedom of piston movement.

Depending on where your black is ...... The transfer layer on the rotor's rubbing surface is one half of the stopping distance equation, and important. It's coloration is very dependent on the formulation of the friction material, how much carbon is in it and how much of the constituents will carbonize under normal braking events.

And when you say "cut", implying being machined, all bets are off as studies we did within my old company and for people like Ford showed that the guy in the auto parts store shouldn't be thinking about a career using a CNC. So if they happened to be generating a 40-60 micro inch finish, with a total runout of under 0.002", great. If not, coloration can be from excessive surface finish just wearing off the friction material in a aggressive manner.

Pictures might help.