Help with dual pivot brakes!
I'm currently working on my Shimano Sora rear brake. Using Park Tools's guide to pivot adjustment, I've been trying to remove the play and binding, but had no luck on the sidepull arm (got the centre pull one working OK).
I have followed the process exactly as Park Tools say. What happens is I have the arm too loose as it is knocking, then I firmly hold the locknut in place and turn the bolt clockwise at most 10 degrees and then it starts binding. I figured that this might mean the unit needs taking apart and degreasing. I did this, even using steel wool and awl on the spring and the points where the arms meet, scrubbing and prodding at it so hard that the finish was starting to come off, so I left it with a few little specs of caked on grease/dirt. I rinsed it, dried it with a hairdryer, sprayed it with silicon lube, tried to adjust it but had no luck. Sprayed more lube on it, still no luck and here I am now. Has any one got any ideas at all, anything would be appreciated. However I did put it back together as the Shimano exploded view of it showed, and also I tried getting it to work without the spring guide, but no luck.
Here are some pictures, is there anything I can do or should I say screw it and pay £15 for a new brake unit? It's only got 450 miles on it so I don't see why I should need to do that.