[mortenk]

Things look a bit dirty down there. I would remove all pads, clean all pistons (they should be shiny) and ensure they can move when pushed with a finger. Ensure the "clips" are positioned properly and grease the sliding pins to ensure the pads are free to move/retract.

 

[mortenk]

The pads must be able to move freely along the pin - otherwise you will end up with uneven wear. I simply wipe off the pins and reapply a thin coat of grease whenever I have them off every few years.