Re: It's good to be back (again!). Canada trip report.

[orin@netcom.com (Orin Eman)]

> Secondly, unlike the Bummer and the rest, our MC has 2(!) shafts with
> the sequential action. During the first half of its travel the pedal
> operates the rear shaft (and its piston), which sends the pressure to
> the rear wheels. Then the rear shaft hits the front one and the later
> starts to move (with its pistons), activating the front brakes.

Usually, there is brake fluid between the two shafts and the front shaft
is operated hydraulicly.  If say the rear circuit fails (eg your caliper
starts to leak like happened to me once), then the shaft will move up,
and mechanically activate the front shaft and the front circuit.  In this case,
the pedal drops about half way without doing anything, then you get
the front circuit only... feels pretty hard because you aren't getting
any help from the rear.  Similarly, if the front circuit fails, the front
shaft will move forward to its stop before the rear shaft moves relative
to it... the rear shaft moving relative to the front shaft is what
operates the rear circuit.

Pretty complicated, but with the design of the resevoir, you could lose
all the fluid from one circuit and your brakes would still work.

Orin.