Rear brakes wearing too quickly

[xung]

I have an '89 240. I changed my rear pads and rotors about this time last year. Recently I discovered that one of the caliper pins of the front driver side brakes had seized, so I fixed that and decided to check the other calipers. The other front caliper was fine. The driver side pads are slightly uneven thicknesses, but both front sets are still pretty thick. The passenger side pads look almost new. They have about 20k on them.

The rear calipers were also fine. However, the new pads I put in last year have worn almost completely. I've only put about 12k on them. There's been no marring of the rear rotors and the pistons are not stuck in the extended position. I've been stratching my head about this. Have I been braking entirely with my rear pads all this time? Is it possible that the ebrake is somehow slightly engaged constantly, and how can I check that? I get decent gas mileage. What else could be causing the rear pads to wear so quickly?

I do not drift.

[180fan]

check em for dragging. If the piston is stuck or if the pins aren't lubed well enough they can drag causing premature wear

[xung]

I don't think they dragging. The wheel is able to turn freely when I jack it up.

Would a 2 degree camber problem cause this? The adjusting bolts are too rusted tight for the mechanic to fix my alignment, without breaking the bolts.

[180fan]

no, that'd mess with your tire life.