I'm trying to remove the "Spring-Loaded Plug" (behind the handbrake lever) that provides access to the caliper pivot pin. I've rotated the handbrake lever out of the way, but still can't seem to get any grip on the plug, even with my largest socket (1-1/8). Is it bigger than this, or is there some other trick to removing it? Would I better off with a ring spanner? I'd really appreciate your advice if you have managed to get this plug off. Thanks.