Hi. I have two sets of older Shimano 7-speed 'brifters'. One does not down shift, the other does neither up or down shift (right side/rear). I REALLY do not want to 'upgrade' to a new Sora and would rather try to make at least one functioning lever out of the two. The levers will move like they are shifting, but no-clicky and not cable movement. They are both stuck in the 1st-gear (big cog) spot.
I have unscrewed the 5mm allen screw on the front of the lever so that the plate came off with the spring inside of it. I am now looking at what is a square-sided 6mm nut/bolt that the allen screw attached. The lever will not come off (easilly) and the nut does not turn (easilly).
Should I even be doing this (I figured I have nothing to loose), and how do I proceed in takling it apart to find the problem? Any ideas on what the problem might be?