Rotor Wear

[bNks334]

I just had the dealer do front brakes a rotors about a month ago, and I noted that there now seems to be uneven wear on my driver side front rotor.

Green area indicates good area of pad contact with the rotor. Red bracketed area indicates area I am concerned about.



Do you guys think this is due to a variance in pad material? Or, does this look more like the caliper is seizing and the pad is dragging? I didn't notice any significant drag when I was tightening the lugs back down... Either way, is it worth bringing the car back in to see my SA?

[Solo_M_Tech]

With this picture i do not see what you are refering too...

[bNks334]

Originally Posted by ApexResistance

With this picture i do not see what you are refering too...

I added another pic I took that day. I am referring to the color variation on the rotor closest to the rotor hat. You might be able to see it better in the second pic.

[mahlerbeatdown]

Originally Posted by bNks334

I added another pic I took that day. I am referring to the color variation on the rotor closest to the rotor hat. You might be able to see it better in the second pic.

I think it's because the BMW pads, and most other pads, are beveled on the edges....

As the pad wears down the beveled area will be flush with the rest of the pad and that's when I'd imagine the color would dissipate. This probably doesn't make any sense, but either way the wear seems pretty similar to mine.

http://c1552172.r72.cf0.rackcdn.com/32406_x800.jpg

[bNks334]

I didn't get wear like that prior to the new brake install and this wear is only showing on 1/4 rotors. Chamfered edges of pads help reduce noise from what I understand as the pad is initially applied to the rotor. They should still have a greater initial contact area than the wear I am seeing, no? I guess I can wait it out to see if variance evens out...

[Solo_M_Tech]

Originally Posted by bNks334

I didn't get wear like that prior to the new brake install and this wear is only showing on 1/4 rotors. Chamfered edges of pads help reduce noise from what I understand as the pad is initially applied to the rotor. They should still have a greater initial contact area than the wear I am seeing, no? I guess I can wait it out to see if variance evens out...

the beveled edge is only on the ends, and from the look of it, the slides on the caliper are not lubricated, and that could cause that bottom edge to drag slightly and scrub off the pad material transferred to the rotor, which explains the color variance. Just a guess.

[NorthernDancer]

OK what I am seeing is maybe 1/4 to 5/16's at the top and then going down to maybe 1/16th at the bottom where the rotor "wear" surface meets the top hat. Is that what you are referring to? If so, yes that's not normal. Without re-reading original post, I think you said other side was not like this. If BMW dealer did this work, I would ask that they do up a work order stating that this is OK. I just looked at my recently changed rotors and they are perfectly centric.

Oh and one good way to check for a dragging caliper is to drive the car 5-10miles or so w/o touching the brakes as much as possible and at the end, let the car coast to a stop. Then go out and touch all 4 wheels around the wheel nuts to see if they are all about the same temperature.

[Dilmorecg]

Doesnt look out of the ordinary to me. Are you experiencing issues with stopping or noise? You could try a bed in process to try and "reset" them.

[bNks334]

Not sure if people are even seeing what I am trying to note, lol. I edited the pics to identify the varying wear on the rotor. Still getting mixed responses as both normal and definitely not normal. I would prefer to be able to state specifically to my SA whether it is or not because we all know that they will try to rush me right back out the door.

[rrinker]

Originally Posted by bNks334

Not sure if people are even seeing what I am trying to note, lol. I edited the pics to identify the varying wear on the rotor. Still getting mixed responses as both normal and definitely not normal. I would prefer to be able to state specifically to my SA whether it is or not because we all know that they will try to rush me right back out the door.

Is there actually a lip there, between the two sections, or is it still smooth across? If the center edge of the rotor is wearing enough to create a lip there, I'd say that is definitely abnormal. Wear should be even across the face of the rotor.

--Randy

[MightyMouseTech]

The pads are bedding in still. Just drive it.

[bNks334]

Originally Posted by rrinker

Is there actually a lip there, between the two sections, or is it still smooth across? If the center edge of the rotor is wearing enough to create a lip there, I'd say that is definitely abnormal. Wear should be even across the face of the rotor.

--Randy

feels pretty smooth still

[Solo_M_Tech]

Then I wouldn't worry about it. Looks like color variation due to the pads bedding in.

[bNks334]

Originally Posted by ApexResistance

Then I wouldn't worry about it. Looks like color variation due to the pads bedding in.

Thanks for your help. I'll ride it out a bit longer.