Current Projects chat and miscellany

They're simple dual pivots. It's unlikely you'll need to dismantle them.

There is likely a little corrosion/dirt in the center pivot (this one is the most exposed to road grime). Take it off the bike, take the pads off it, and shoot it with some wd-40 or gt-85 while actuating it manually to work it in. Then maybe even apply a drop of lube to each pivot, wipe off the excess thoroughly and re-install. It should be fine, and I doubt the corrosion on the spring is the problem.

This. 99 times out of 100 this sorts out any stickiness. If it's still a bit sticky then a period of immersion in a lubricant usually sorts it out that 1 problematic time.