[V6-12v] stopping problems

[Elliott Potter]

I'm frequently wrong about this stuff, but I still disagree:

On Mon, 2 Aug 2004, [iso-8859-1] mike wrote:
> The v6 na cars have the bomb too...

The "bomb" on 5-cylinder cars is a hydraulic pressure accumulator, which
has three hose connections (two are 2000+ psi hydraulic connectors),
whose function was to maintain *hydraulic* pressure.  This was necessary
because turbo cars used a hydraulic brake boost system, as opposed to a
vacuum assisted brake system, and the bomb (which was charged with
high-pressure nitrogen) was there to maintain hydraulic pressure to the
brake system.  It's called a bomb because it looks a bit like the German
M24 and M34 ("potato masher") grenades.  I don't know for sure if non-turbo
5-cylinder cars had this but I don't think they did.

Cars with the 12v V6 use a vacuum assisted brake system, and do not need
a hydraulic pressure accumulator.  What the 12v V6 _does_ have is a
vacuum reservoir, which is a round plastic ball that sits in front of
the intake manifold next to the ignition coil packs.  It looks a bit
like the ACME brand bombs you see in cartoons, so I guess you could call
it a bomb, though it's less likely to explode if mistreated like the
turbo cars' bomb is (since it's just an empty plastic ball).  The main
function of the vacuum reservoir is to provide vacuum for the intake
manifold changeover valve, since that valve operates at high engine RPMs
where the vacuum provided by the engine is reduced.

The vacuum brake booster gets vaccum from a different part of the engine
and is not connected to this reservoir.

Having said all of that:
- the large diameter vacuum lines that feed the brake booster do tend to
  crack, and that could cause braking issues (though it's not as
  likely).  Those lines plug in to the front of the intake manifold
  unless you have a very early 1992 build.
- the connection to the vacuum reservoir commonly cracks, and the
  resulting vacuum leak can cause the sorts of problems that vacuum
  leaks normally cause; generally rough running and/or CELs.

*shrug*  Like I said, I could be wrong on this.  I'm not doing a very
good job of keeping up on 12v trivia since I don't have a 12v car
anymore.
--
Elliott