Last year I completed a twin disc conversion of my 750F1 (see avatar). When it was all done I bled the brakes (with silicone fluid) and everything seemed fine except for a blocked pressure relief hole in the Goldwing MC which was quickly rectified with an E guitar string (at tip I found elsewhere in this forum). A couple of days later I was surprised to see there were some fluid leaks from some joints which I set to and fixed by tightening everything up within an inch of its life. All seemed fine except a day or two later I noticed the left caliper was weeping slightly so I just left it and got on with other projects i.e. a 72 350F, 78 750F2, 79 DT250 and 77 DT125.
Sooooo, today I finally got jack of the F1's brake fluid dripping onto the garage floor and decided, at last, to do something about it.
When I did the conversion I was sure I had thoroughly cleaned out the calipers and rebuilt them with new seals and pistons. I took the caliper apart, removed the piston and seal and, using a dentist type mirror, had a good look at the seal groove. Sure enough I had missed some caked-on debris. Cleaned it out again, reassembled and refitted back on the bike.
At this point I had a closer look at the right caliper and it too had a very slight weep but not quite enough to drip fluid on the floor, so it too came off and was recleaned. When all was back together I realised I don't have fluid left to refill the MC. Bugger. Local auto parts stores around here don't stock silicone, Dot 5, fluid. Kart shops stock so in the next day or so I'll be paying one of them a visit.