# Discoloration on brake rotor. What is it?



## jtwoods4 (Dec 22, 2011)

Hey Guys,

Today I removed my rearend on my 69 GTO. I noticed some discoloration on the rear driver side Wilwood disc brake rotor. Anyone know what this is? Here is a video showing what I am talking about.


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## GTO JUDGE (May 14, 2005)

Looks to me like heat build up. E-Brake hanging up? Brakes not adjusted right when applying they are rubbing?


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## geeteeohguy (Feb 2, 2008)

Blue means heat. Does your set up have internal drum parking brakes inside the rotor hat? If so, they could be dragging or set too tight. You didn't show the rotor surface, so I can not tell if it's blue too, and the heat from the working surface is bleeding over to the rotor hat.


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## ALKYGTO (Mar 29, 2010)

I definetly agree with both of the above. If the rotor "hat" is also the drum for the parking brake I would say that it is (or was) adjusted too tight. Can you feel/hear any drag when you turn the axle? Are the parking brakes self adjusting on these? 

Since my car is a stick I use the parking brake all the time and more than once I've left it engaged and driven off. I really can't tell just that the car feels a little sluggish lol. Theres enough power there and noise that it really is hard to tell and I feel pretty foolish when I figure it out  :lol:. If you've done this even once it would be enough to discolor the rotor and the coloration is'nt going away until unless you "clean" it off by polishing manually.


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## jtwoods4 (Dec 22, 2011)

I didnt notice any dragging but I also have a stick. There have been many times when I was on a steep hill and need to release have the parking brake on while starting off. Then releasing the brake as the car gets going. I bet this caused the disscoloration. I didnt think having the brake on for a few feet would do this. The break is not dragging though. Anyway, thanks for the feedback.


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## GTO JUDGE (May 14, 2005)

jtwoods4 said:


> I didnt notice any dragging but I also have a stick. There have been many times when I was on a steep hill and need to release have the parking brake on while starting off. Then releasing the brake as the car gets going. I bet this caused the disscoloration. I didnt think having the brake on for a few feet would do this. The break is not dragging though. Anyway, thanks for the feedback.


It doesn't have to be engaging much to cause the heat discoloration. Just enough to touch the disk. If it were me I'd take it apart and lube well and have a helping hand work the e-Brake to make sure its not hanging up at all. Hopefully its just a slight adjustment of the cable?


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## geeteeohguy (Feb 2, 2008)

If you can turn the rear wheels easily with little or no drag, no worries. All due respect, I recommend finessing your uphill take offs. Shouldn't need the ebrake if you're fast with your feet!!


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