help 03 z71 will not stop eating brake pads

[Blackout]

Have replaced EVERYTHING on this damn trucks rear brake system. Calipers including pins and slides, pads, rotors, I even replaced the brackets thinking they could be bent. Both inner pads go out at the same time within 15k. Ive got almost $1000 into it and still having the same problem. What in the fuck is going on here?

 

[Tiki]

$1000? What kind of pads and rotors do you have? What's going wrong when they fail?

 

[Blackout]

Powerstop and on my 3rd set of pads, also replaced brake lines. Let the shop do that though shit was nasty was about $300. It wears them down to bare metal in about 15k. I replaced the front pads at the same time as the first set on the rear and they're still at 75% atleast. I'm not heavy on the brakes either.