to make a long story short, i found out that the rubber cup seals inside the NOS master cylinder that i bought were in fact bad, in spite of my careful inspection & assembly. theres fluid leaking from one of the elbows and a small puddle on the floor:
there was also some very light corrosion in one of the wheel cylinders that was preventing its piston from moving through its full stroke, which eventually broke free that morning, causing the collapse of the pedal under heavy pressure. that part cleaned up fine, but the real ball-buster is that i have to take the MC out again! the only positive about this whole mess is that i can use the seals from a rebuild kit intended for either a late type 3 or even a Rabbit...any 19.05mm (.75 inch) ATE cylinder, really, making the solution relatively cheap (around $20).
i was so stunned when all this happened that i just sat there, looked up at the rear view mirror into my own eyes for some kind of explanation, then just whispered a "WTF?". i pumped the pedal a few times, but no change. if it had just been the wheel cylinder popping into place then i should have been able to recover at least some pedal pressure because the MC would have drawn more fluid from the reservoir and pushed it on down. but there was no improvement, and subconsciously i knew what that meant, ultimately. and i thought 1970s motorcycles had shitty brakes... maybe i should be running a '75 GL1000 setup, never had this kind nightmare with them, and they live outside all year.
