<VV> dual M/C

[David Heath]

I have to chime in on the dual M/C conversation.  I am trying to prep a car
for my son to use once he gets his license (if he ever brings his grades
up...), and part of that process was to upgrade to a dual M/C setup for
safety.  I am familiar with how the dual M/C units are designed - it is a
little more involved, but basically, the first plunger has a rod attached
which will contact the second plunger even if there is no fluid pressure in
the first chamber, so you should always have brakes.  I had heard all the
talk about the "shuttle valve/light switch" thingy but felt that if one of
our vendors offered a kit without the part, you probably didn't need it.

I installed the kit as supplied and then tested it exactly as mentioned
(loosen a bleeder screw in the back and press the pedal) but the pedal went
to the floor.  Re-bled the system and then did the same test to the front -
pedal went to the floor.  I could not believe it so I repeated the test
several times.  Emailed the vendor and they said that is to be expected but
that it was good. (huh? Really?)

Now, based on the exploded diagrams I have seen, you should not need the
shuttle valve.  The only explanation I can see that makes sense is that (as
mentioned before) my '65 brake pedal does not have the same travel as the
factory dual M/C cars.  Any of you guys who have access to a bunch of spare
parts have a way to verify this?  I am now one who has a dual M/C setup
which is no safer than my previous single M/C setup (as near as I can tell).

Dave Heath
Cypress, CA
'65 140/4