hi.
no , that is not classic brake fad.

Sounds like a tired master cylinder to me.
what I call 'sinking pedal'.
you can test for it with the van not driving, and just put steady foot
pressure on the brake pedal.
It should not sink even with your foot hard on it for an hour.....or you
know, 10 full minutes.

if the pedal sinks doing that test ...likely internal leaking from chamber
to chamber within the MC  - or out in the wheels, like rear wheel cylinders.

Brake fad is when you have decent pedal, but brake pads and calipers have
gotten so hot from continued or hard downhill use, that the brake fluid
starts to boil...
then you have essentially no brakes, are barely any.

btw ...
continued light use ..or steady light use, as in a long decent is not the
right thing to do at all.
that just builds up heat.
 Instead...use the brakes hard enough to drop some speed, then don't use
them ...
given them some cooling time...then use again a little harder, then let cool
etc...

continued light or steady use is not right at all.
Even in regular non-hill driving.
Excessive light braking contributes to brake squeal, maybe even pad glazing
..
brakes work much better when 'exercised' more.
As a regular practice, on any car, you should use the brakes to about say
2/3 of their ability, intentionally, now and then.  Like for off ramps
...slow from 50 to 30 harder than you normally would once in a while. Don't
over do it.
 Just avoid lots of very light brake use, or lots of steady light
application.
And brake in new pads properly too.   Another subject.
Scott
www.turbovans.com
----- Original Message -----
From: "Paul" <wognacious@GMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Thursday, June 24, 2010 11:54 PM
Subject: Brake question......

> Is this what I've heard described as "brake fade?" I'll be going down a
> hill
> and the pedal feels normal, if there is such a thing, and once in a while
> it
> feels like the pedal all of a sudden will go right down to the floor
> board.
> If I give it a quick pump everything feels good again. That feeling of no
> back pressure is a bit unverving when going down hill and I'm sure that's
> not the way it should be. Do I need to bleed the brake line?
> Any insight will be gratefully appreciated,
> Thanx,
> pAUL