Re: How can you tell if "the bomb" is bad?

[frankbauer@thevine.net]

some ignorant putz sez:     =8)
>Please forgive my ignorance -- I'm a mechanical putz.
>Does this apply to all cars -- or just Quattros?  I get 2-3 pumps on my
>Grand Cherrokee (don't buy these cars) -- does this mean that this vehicle
>has a bad bomb or just a very small bomb?

most cars use vaccuum assist for brake boost.  the vac reservoir is a
large round object mounted on the firewall behind the brake master
cylinder.  vac is provided by the engine.  forced induction engines (such
as audi turbos) are not producing vacuum while running under boost (by
definition.)  therefore you could have a situation where you need brake
assist while running under boost.  this led audi to design a hydraulic
brake assist.  the power steering pump was replaced by what is
essentially two pumps on one shaft, one for power steering and one that
provides pressurised hydraulic fluid to a pressure accumulator (the
bomb) which is the reservoir used to assist braking.  i doubt your JGC
has hydraulic brake assist.  i would hazard a guess that nearly all
turbo quattros use the bomb.  likely some non turbos also use it and some
early urqs may not.

frank