Pierburg Pump, Brakes, etc., etc.

[Louis-Alain Richard]

Maybe someone already mentioned this, I don't remember well...

Could the root cause of all this behaviour be the brake fluid ?

IIRC, used brake fluid has a much lower boiling point than fresh one, so
maybe the underhood temps are just enough to make used fluid boil ? All
this lockup thing may just be resolved by fresh fluid ?

Louis-Alain



> -----Message d'origine-----
> De : quattro-bounces at audifans.com
[mailto:quattro-bounces at audifans.com] De
> la part de Brett Dikeman
> Envoyé : 12 mai, 2006 00:18
> À : Steve Sears
> Cc : quattro at audifans.com
> Objet : Re: Pierburg Pump, Brakes, etc., etc.
> 
> 
> On May 10, 2006, at 3:58 PM, Steve Sears wrote:
> 
> > I cut horizontal slots about 3" long and about 1/2" apart in
> > a strip in the wheel well liner, then used a heat gun to bend the
> > plastic
> > into louvers.  It's set inside the wheel travel, and haven't
> > noticed any
> > dirt in the vicinity of the louvers since then.  When the fan comes
> > on, the
> > heat blasting out of the wheel well is amazing.  I have also
> > removed the
> > foam rubber piece from on top of the fender liner and now there's
> > some heat
> > escaping through the driver's door jamb.  I may do the heat shield
> > over the
> > master cylinder as well - it's on my 'round tuit' list with
> > replacing the
> > heat shield on the injector lines.
> 
> I know the temptation to armchair engineer is strong with many of
> you ;-) but give thought to the fact that Audi didn't see fit to
> install a vented wheel liner in any type 44 that I know of (I believe
> they did in the S-cars but only because of the ducted intercooler)
> and I have NEVER seen a vehicle with a heat shield around the master
> cylinder, even in an insanely packed engine compartment like the TT.
> Maybe it'll work and there will not be any downsides, but I would be
> concerned that there is -some- reason Audi didn't do it, other than
> "hee hee, let's make them buy new master cylinders every few
> years" :-)  I would also say that if you are going through MCs every
> few years- something's wrong.
> 
> Temperature of air coming out the radiator are pretty toasty, but I'd
> be astounded if they surpassed 200 degrees.  If your master cylinder
> is sticking, you need a new master cylinder, because it's failing.
> The one in my 200q20v started doing this, and I replaced it with a
> shiny new one- zero problems since.  Given the old MC lasted well
> over 160,000 miles and 15 years, I felt it wasn't a big deal.  It
> failed shortly after the car had been parked for a couple months, so
> I think the too-old brake fluid and storage are probably what killed
> it- not necessarily age.
> 
> If you want to lower underhood temperatures, the safest and most
> effective way bar none is to coat the exhaust and downpipe.  You can
> wrap it, but that won't be as effective and will reduce manifold
> life.  You'll get better emissions (EGTs at the cats will be higher
> quicker), and higher EGTs will offset the smaller interior diameter
> (unless you extrude-hone the manifold+downpipe, in which case you'll
> get the best of all worlds!)  You'll probably see less heat soak of
> the intake manifold on the 10v's, less heat buildup by the airbox
> intake, and the lower underhood temps will make for longer component
> life.  All sorts of nice side effects!
> 
> Brett
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