Well, I've been in as far as you have, but no farther. I got a 'BRAKE FAILURE' light one day that would not go away. Against other's better judgement, I replaced my switch. It has been suggested that it is often better to simply replace the whole junction block, rather than fiddle with the finicky switch. I ordered a switch rebuild kit, it came with the nylon outer screw-in 'shell', o-ring, pin and spring. My switch had become contaminated by dirty road spray (NOT brake fluid from inside the block.) It was a bit of a bear to get the thing out, but once out, I cleaned the hole out, dried it well, and put the new parts in. Working that nylon piece in took another dose of patience. Once the whole unit was back together again, it worked fine.
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Speed Racer, '83 240 R, '74 164 E, '93 940 OL1 (Manchester, CT)