Thanks, RR2, for that ray of light. The rear caliper on the (2014 V7) Special also slides on two pins. The large boot is mangled, likely on original assembly, allowing road grime to accumulate around the pin, eventually preventing the plate sliding back, thus keeping the pads on the rotor, the fluid boiling, and brake failure. I was told that spare boots were not available (but those Pegaso ones looks suspiciously similar). Thorough cleaning enables it to work again, but that has to be done more or less regularly. I was told to just remove the boot, but not pleased with that. A new boot is a better option than a new caliper. Next time I clean it up, more photos & careful measurement will ensue. And perhaps a closer inspection of some Stelvio's calipers for comparison. Things are looking up.
