Date: Wed, 19 Jul 1995 08:43:43 -0400
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: "Chris Chubb" <cchubb@ida.org>
Subject: Re: 71 Bus Brake Booster
Russ Van Ness sez:
/I'm resurrecting the aged (currently disconnected) power assist system on my
/71 Bus. The original large vacuum hoses are cracked and falling apart. Is
/it possible to replace these with heater/coolant hose or is there a "special
/vacuum-only reinforced rubber" hose needed for this application?
It must be able to support about 50% vaccum, or .5 atmospheres of vacuum
in a length of 15 feet without collapsing. Heater tube is pressure
reinforced, not vacuum reinforced. This stuff is EXPEN$IVE, unless
you got some buddies in the chemistry business. I think the dealer
quoted me $185 for the hose. (Ouch!)
/It appears my master cylinder has been leaking fluid where it meets with the
/booster. I suspect this bodes ill for my (booster) diaphram as I've read in
/the archives. Can anyone recommend a good source for the booster should I
/need one?
Dont try to rebuild one yourself. You can, but it is like open heart
surgery. I took one apart (junker) to see how it worked, and I could
have never got it back together well enough to trust my life to it.
Let the people with experience rebuild 'em. Some junkers are good units,
but make sure you can return it if it wont hold vacuum.
/Also, I can't seem to find the vacuum line check valve that the Bentley
/manual mentions (prevents pressure from an engine backfire from damaging
/diaphram in booster?). I checked the vacuum hoses and found no such valve.
/Do I need a valve specifically for my bus or can I go generic on this (i.e.
/one from a Dodge Caravan, Ford Windstar etc...)
Any brand that fits the hose will work. Mine goes right next to the intake
manifold, on about 1 inch of hose. Not only does it prevent backfires,
it also keeps enough vacuum in the hose to stop the car if the engine
stalls or somethng. Enough for about 3 pumps. I think it cost $7 from the
VW dealer. (About the same as FLAPS, but it took two days) (victim of
engine fire)
/Curiosity question: There is a hose that comes off the front of the power
/booster that joins to a metal tube that disappears into the wheel well sheet
/metal. Is this some type of vent tube? If so, why is it venting into my
/body panels???
This is where the air enters the vacuum booster when you let off the brake.
It is an intake line, and no brake fluid flows in the line (hopefully).
PS, Thanx for the word about the brake rotors. $20 cheaper than anyone
else. Mine could not be turned last time I tried, too thin.
--
-- Chris Chubb (cchubb@ida.org) - (703)-845-2287 [Alexandria, VA, USA]
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