A visit from Mister Dumbass (and a valuable lesson learned)
While replacing my brake shoes a while back, it seemed like a good idea to replace the spacer washers on the actuation cams. It also seemed like a good idea to use thicker ones (for no particularly good reason... in hindsight). When the job was complete, neither the front or rear brake would release fully. The extra width of the spacers was just enough to cause the retainer nut to clamp down on everything, thus interfering with the movement. I reinstalled the original, thin spacers and that was that, although the length of time spent on this bit of routine maintenance ended up being double what it should have been.