There was no evidence of binding; rather, the mechanism appeared to be blocked from moving at all. I spent a long time yesterday trying to troubleshoot it. What seemed to be the issue was that the bell crank (and associated linkage) was sitting in such a way that the linkage was trying to pull straight down - when it should have been offset enough to allow the crank to rotate (hard to explain without visual aids). I removed the brake arm/lever and the bolt holding the bell crank, looking for wear in the bushings, etc. I found nothing amiss. After over an hour trying to reassemble the whole mess (the linkage was keyed to its respective holes in a way that didn't allow each part to be put in place - it all had to go in at once!), the damn thing started working...
I've been around long enough to know that I didn't "fix" anything, so the problem will likely return. At least I got to cut the grass, though! The brake operated fine throughout. Fingers crossed.
