I have an tandem with Dia-Compe cantilever brakes -- the type where spring tension is adjustable with a cone wrench. Only one arm of each pair has this adjusting mechanism -- the other arm adjusts by setting the end of the spring in one of three slots on the tab brazed on to the frame.
Recently, after riding in some wintry weather and then leaving the bike to sit for a few weeks, both the front and rear brakes seized up completely. I could barely move the brake arms with my hands, and needless to say they wouldn't spring back after I applied the brakes. However, only the arms that adjust with a cone wrench seized up.
I tried removing the brakes, cleaning and lubing, and putting them back together, but still no luck. Either the bolt is too loose and the tension adjuster moves around, or it's too tight and the whole arm gets stuck.
I'm wondering if I put the brake back together wrong, but it there seems to only be one way to assemble it. There are four parts: the arm itself, the spring, a little plastic bit that fits around the spring, and the metal piece that adjusts the spring tension.
First I set the spring into the arm:
Then I set the black plastic bit over the spring:
Then I put the metal adjusting piece on, fitting the slot onto the end of the spring that's sticking out:
And finally I bolted the whole thing into the cantilever boss on the frame.
Am I missing something here?