Does it pull to the opposite side? Or make any noise?
I'd get it looked at. It may have been there a while and is no longer there. But if something is still jammed in the pad, if it were me, and it isn't, I'd take a look.I've seen this before and wouldn't be concerned unless you have a braking issue. And this isn't a nuclear explosion so root cause analysis will not be required.
I have and it is definitely a ledge. I've had plenty of grooves in the past but never a ledge which is why this is so alarming. I will def ask my SA about it when I am at the dealership next week.Have you ran your finger nail across the rotor to see if that is a groove in the middle or a lip to drop off? It looks like a groove to me. I've had that happen before on a different car. It was from a stone that got caught between the pad and the rotor. The stone cut a groove into the rotor. Pad was removed to remove the stone and reinstalled. Groove was still on the rotor but braking wasn't affected as far as I could tell.
Yeah poor choice of wording. I just meant the upper part of the brake pad. Since there are 3 pistons (or whatever the 3 black circular objects are called) I just assume the outermost one could be applying contact independent of the two innermost pistons. Maybe the brake pad is broken and the piston is free to move independently of the other two?Um... Where to begin?
1. There is NO upper brake pad. There is a brake pad on the inside and outside of the disk/rotor held in place by the caliper.2. The caliper piston location can be seen in the photo above by the circular arc by the bleeder nipple cover. That piston cannotpush against the pad and hence the disk in a manner to yield the stepped wear depicted.
Potential explanations for the uneven ware might include:
1. Defective material composition of the disk exhibiting this uneven wear2. Defective brake pad material. Perhaps part of the area of pad material composition is harder than the rest of the pad surface?3. Contamination of the assembly by the introduction of a stone, etc. that may have become wedged into the pad-disk gap
This should be disassembled in order to determine what is the root cause for the uneven stepped disk wear.
Yes this exactly. It is 100% a ledge with a +/- mm difference in thickness on either side of the ledge. The inner portion of the rotor is the thicker of the two which is why I think the outermost piston is somehow applying uneven pressure. I just don't understand how it could be such a defined line unless the brake pad is broken allowing the outer piston to apply greater force than the inner two. Will definitely ask about it on Friday.So, what looks like a grove in the picture above is actually a ledge; and the lower portion of the rotor face is thicker than the upper portion of the rotor?
Not sure how that would happen, unless the bottom half of the friction pad is missing. The shop should be able to sort out the problem fairly quickly.