The test for the booster is to pump up the brake pedal until it is hard and
then start the van.  The pedal should drop a little.  However you could
still have a leak.  You could pull the vacuum line on the booster and
pressurize it with air, then use the soapy water technique to find a leak.
That sounds complicated but is much easier than replacing the booster which
requires pulling the dash along with some finger gymnastics to get at the
bolts in the back.  Also a new booster is pricey.  They list for $414 at the
dealer.  I have them listed on my site for $325 but I could probably do
better on that price for a list member if you found you needed one.  It is
not normal for you to hear a hissing sound when you press on the brake
pedal.  And the brakes should feel good on your van (firm, high pedal) or
something is either leaking or out of adjustment.

Thanks,
Ken Wilford
John 3:16
http://www.vanagain.com
http://www.strictlyvwauctions.com
http://www.eurovan.org
http://www.vwcabrio.org
Phone: (856)-327-4936
Fax: (856)-327-2242 

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Troy
Sent: Wednesday, February 07, 2007 7:59 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Brake Booster question

Hi there:

Have a question about a possible vacuum leak from the brake booster. When I
depress the brake pedal I hear a very low-level hissing sound, coming from
what sounds like the brake booster. I have not owned my van for a long time,
so not sure if the sound is normal for the vans or if I have a possible
vacuum leak. It has pretty much been there since I purchased the van.
Braking power is okay, not great, but for what I am told the brakes on these
vans are not the best in the world anyway. I just  bleed the lines this past
weekend, and the hissing sound is definitely not as loud/strong. So, is this
a problem or just normal behavior for the van? FWIW, if I pump up the brakes
and then start the van, there is just a small release of pressure, but it
does hold. I'm guessing there is a small vacuum leak, but I just don't know.
Suggestions?

Troy