Cable.............came.............loose?
I dont think so, the brakes still move, but when they touch the rim they just don't do anything.
Completely hypothesizing here, but is there any chance that you pulled some cable through the pinch-bolt somehow? (Are these V's?). Are all of the housings still in place in their housing stops?Are you using new brakes/levers/cable? You could have just set everything into place, but I don't think you would notice the amount of slack you talk about.
they are canti's, and they are pretty old. (before v-brakes were invented) Just so you know, they are bottom of the line shimano, on my bottom of the line huffy.