Black discoloration on the brake rotor.
07-06-2003, 11:17 PM
#1
Nordschleife Master
Thread Starter
Black discoloration on the brake rotor.
Normaly my brake rotors are a shiny metalic color, except when the car has to sit for a week or so, then there's a light surface rusting.
However, after a series of high speed runs into cruves that required brakeing from about 120 to 70 to be comfertable, I've got a light black ring on the rotors that looks almost like they are scroched. I only noticed this because at one point in the route, there is a train crossing, and there was a train this time, so I got out of my car, and walked around for a bit, and noticed this.
I've done these serises of curves before in exactly the same mannor, but I've never stoped to look at the brake rotors. As far as I know, they've never had that blackish look before, but like I said, I've never looked dirictly after doing the curves.
Right now, the rotors are almost back to fully shiny again.
I didn't experence any ntoiceable brake fade, and have been mostly impressed with the 928S's brakes, as if I'm not careful they'll lock up the tires on anything that I've ever done. A could of times, doing repaeted 120 to 10 mph brake runs, (down the road, into a drive way, repeat...) I've experenced brake fade, that that felt like it was from the fluid boiling. Have to change it out in the not so distant future.
Any suggestions as to whats causeing the blackish discoloration?
Thank you.
However, after a series of high speed runs into cruves that required brakeing from about 120 to 70 to be comfertable, I've got a light black ring on the rotors that looks almost like they are scroched. I only noticed this because at one point in the route, there is a train crossing, and there was a train this time, so I got out of my car, and walked around for a bit, and noticed this.
I've done these serises of curves before in exactly the same mannor, but I've never stoped to look at the brake rotors. As far as I know, they've never had that blackish look before, but like I said, I've never looked dirictly after doing the curves.
Right now, the rotors are almost back to fully shiny again.
I didn't experence any ntoiceable brake fade, and have been mostly impressed with the 928S's brakes, as if I'm not careful they'll lock up the tires on anything that I've ever done. A could of times, doing repaeted 120 to 10 mph brake runs, (down the road, into a drive way, repeat...) I've experenced brake fade, that that felt like it was from the fluid boiling. Have to change it out in the not so distant future.
Any suggestions as to whats causeing the blackish discoloration?
Thank you.
07-07-2003, 12:23 AM
#2
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Location: Ft. Lauderdale FLORIDA
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I've seen rotors on high performance brakes that have been overheated become kind of a dark purple-blue color...
If they are still working right, I'd not worry about it. YMMV~
N!
If they are still working right, I'd not worry about it. YMMV~
N!
07-07-2003, 02:21 AM
#3
Nordschleife Master
Thread Starter
I know I'm beating the heck out of the brakes when I do this, and a brake failure would not be a good thing. Why? The 928 was not designed with the soft ground in a farmers feild. (Trust me, I know...) It's also not designed to be launched of the outside edge of an slightly banked turn. I have no personal experence with this, but logic says it's bad.
I like to know what happening, so I can fix, or innore it as required.
Btw, I've got some sort of metalish brake pads that squeek like heck, but make no dust. When I beak on the braks hard, the squeeking goes away for a while, so I do it from time to time. Also, the high end vibration when I jump on the brakes at over 80 get lessened. Anyways, thats my excuse.
I like to know what happening, so I can fix, or innore it as required.
Btw, I've got some sort of metalish brake pads that squeek like heck, but make no dust. When I beak on the braks hard, the squeeking goes away for a while, so I do it from time to time. Also, the high end vibration when I jump on the brakes at over 80 get lessened. Anyways, thats my excuse.
