perfect black/dark rings on my rotors

[blipblop]

I've been meaning to ask this. I changed my pads @ 40k. I replaced them with the Axxis Deluxe Plus. Ever since then I have these perfect black rings on my rotors. Does this mean that the contact is uneven or something?

FYI I just slapped the pads on. I didn't do anything with the rotors when I changed pads. The shims are all back and in the right place. I have 46k now and my brakes are fine. I just want to see what the problem is so I don't have problems later down the road. thanks.

Should I re-bed them in? I don't want any long term damage to my car and I was wondering what fixes I can do to get rid of this. Thanks

 

[Analog]

Why didn't you have them turned?

 

[blipblop]

I didn't know i had to turn my rotors. It was my first time changing them on my car. The car forum elsewhere said it was just fine to slap them in. My couple of my friends did the same thing and they have the rings as well. Anything I can do to save it? Or is it pretty much get a new set of rotors/pads when these go? I've driven about 7k miles on them without any problems

 

[Analog]

Originally posted by: blipblop
I didn't know i had to turn my rotors. It was my first time changing them on my car. The car forum elsewhere said it was just fine to slap them in. My couple of my friends did the same thing and they have the rings as well. Anything I can do to save it? Or is it pretty much get a new set of rotors/pads when these go? I've driven about 7k miles on them without any problems

I generally have my rotors turned when I change the pads, because its cheap, and I like to have a nice surface when the new pads go on. I guess there are circumstances when turning is not necessary, but if you're going through all the trouble and they're staring you in the face....


I'm not real sure about the rings though. I'd guarantee that turning would get rid of them, at least temporarily.

 

[Eli]

Why do you think it is even an issue?

Are the rings merely color, or is it a pit or raised spot?

 

[boomerang]

Pics please.

If the rotors are in good shape, it's actually not necessary to machine them. In most newer vehicles, you may not be able to machine them even once. There is just not enough material on them to do so. Weight savings and all that. Having said all that, I'll get mine turned too if stock is available regardless of their condition.

A lot of folks aren't aware that the dimension cast into them is not the minimum thickness they can be machined to, it's the throwaway dimension.

I'm thinking the rings you are talking about are where the pads are riding on the high spots on the rotor. You say you have good braking, so I think you are fine. The pads will eventually conform to the unevenness of the rotors and your braking will be even better.

I wouldn't sweat it. Pics would help though.

 

[Pliablemoose]

On some of the newer cars, the manufacturers do not recommend turning (resurfacing) the rotors, just replacing them.

That being said, most rotors can be turned and many auto parts stores can turn them for you, they'll check them first to ensure they can be turned safely, leaving enough material so they won't be prone to warping under hard use.

 

[zerocool84]

Originally posted by: Pliablemoose
On some of the newer cars, the manufacturers do not recommend turning (resurfacing) the rotors, just replacing them.

That being said, most rotors can be turned and many auto parts stores can turn them for you, they'll check them first to ensure they can be turned safely, leaving enough material so they won't be prone to warping under hard use.

yea that goes for my car. not recommended to resurface them but just to buy new rotors.

 

[milesl]

When installing new pads,there is a wear in period when the brake pads have to wear into the rotors.Even when you get rotors turned they will not be a perfect fit to the new pads due to the pads and and caliper not being perfectly shaped.
The black rings are areas that got hot where the rotors first met with the pads when they were installed.If your brakes stop fine and are not pulsing when stopping I would not worry about it.
To prevent this and promote fast wear in of the pads most good brake installers scuff the brake rotors and pads with 80 grit sandpaper before install,then drive the car for about 40 mild stops under 45 M.P.H.This wears the pads in faster and prevents hot spots on the rotors that form from high speed breaking with less than ideal pad to rotor contact.