I've noticed that with hard brake application, I slight hissing sound can
be heard coming from under the dash in our 83 westy.  I fear it's the brake
booster?

You don't need to be moving to hear it.  When idling, if I push in the
brake medium-far, I hear nothing, but pushing down *hard*, I hear the
hiss.   It seems like the noise is on or off, and doesn't vary continuously
with depth.

There is no fluid leak....

Is this a problem?  I don't usually push down the brakes hard, so I'm
wondering if its down this for a while without me noticing.

I'm afraid to ask the next one...
do I need to remove the dash to replace the booster?

Thanks!
Wes