Did a shop ever replace the rear pads in the past? Perhaps the pins were corroded and they replaced them with the wrong size. Just a thought.
According to rockauto.com, it's Dorman part # HW5066. Might be worth a shot for 5 bucks...
DORMAN Part # HW5066
Rear
$5.25
DORMAN Part # HW14154
Front
$5.68