I'm stripping down an early 80's vintage Miyata 912 - all Shimano 600 equipment. I've looked in Sheldon Brown's website and done searches here, but it's still not clear how to remove the brake assembly. I've got a hex bolt head, washer, brake arm, washer, spring retainer, "funny looking bumpy spacer?", brake bridge. I really need to get front and rear brakes apart and don't want to break anything. Thanks!