Uneven brake wear?!?

[M3sedan]

As I was driving in to work today, I noticed an odd sound from the front passenger side like my brake pads were dragging against the rotor. Not a squealing noise but more low tone of metal to metal contact. When I stopped to look at it, it looked as if there was no pad left!! However the other side had plenty of pad left. Does anyone know why this would wear so unevenly? Is this a caliper problem? Any help is appreciated. Thanks

[sped here]

Yeah, it might be a caliper sticking. If you are a DIY guy the rebuild kits are cheap at bimmerparts.com.

Check it over though, the pad could have been defective and crumbled (or maybe the guy who swapped them last time tipped a few at lunch and forgot a side

[M3sedan]

I believe it is the caliper. Thanks for the suggestion. Is there a way to tell if the caliper is sticking before it gets to this situation? I didn't even realize this until the brake pad was completely worn down. Thanks

[sped here]

I'd think you would have noticed it pulling to one side

[M junky]

My 2 cents,Check the suggestions above first,if it isn't that,
on one of my older cars I had the same problem.I checked everything and just could not find the prob.So after talking to a number of people,someone told me to check the hard lines right
before the soft lines going to the calipers.I looked thoroghly
until i found one of the lines to the caliper that had premature wear, was kinked a little,Looked like a wrench or larger object
hit it.I bought a replacement hard line from the dealer(Nissan at the time)and swapped it in.Never had that problem on that car
again.I'm not saying this is your prob,but if nothing works,
doesn't hurt to check.

BTW-Sorry for blabbing on:

~Reagan