Originally Posted by
cny-bikeman
The springs are quite strong so are very unlikely to be the issue. In the same vein lubrication is not likely the issue either - it makes things move smoother but that brake will not bind just from lack of lube.
The pivots could very well be the issue, but there indeed is no "adjustment" of them per se. The pivot bolt is firmly tightened onto a bushing that prevents the bolt from pushing on the arm and binding it. The nut in the back is merely there to help lock the bolt in place. If one severely overtorques the pivot nut the bushing can be distended, causing the pivot to bind.
Thank you, as I said, it's been a while. In this case the adjustment must be made with a file, thinning the arm (or a washer) so the bolt and nut can tighten on the bushing without binding the arm.
In any case the OP can discover this for himself. If when he removes the nut the bolt is free to fall out, it's not adjustable. If without the nut the bolt is still threaded to the bridge then it is. Either way he can deal with it accordingly. I only offer the threaded bridge possibility because I have vague memories of dealing with brakes where the back nut fell off but the bolt stayed in place.