I went to GGB4 over the past weekend. I was happy that I got 21 MPG round
trip and that included plenty of mountain climbing in 2nd and brake fade on
the way down.

Anyway, 1 mile from my house yesterday I almost rear ended a pickup truck as
my brake pedal went all the way to the floor. Pumping did not help. My pads
and shoes are less than a year old and the system was bled a month ago.  I
left a message at my mechanics to fix this but is this most likely the
master cylinder on it's way out? Should I pick one up at Bus Depot before
bringing the van over? Is this something I can replace myself?

Thanks,
Bryan