[s-cars] A Different Brake Light Question
fastscirocco_2000 at yahoo.com
Sun Jun 28 18:49:34 PDT 2009
I am not familiar with the banjo bolt screens....where are they?
----- Original Message ----
> From: Tom Green <TRGreen at comcast.net>
> To: Scarlist <s-car-list at audifans.com>; Douglas Fifield <douglas.fifield at gmail.com>; Fred Munro <munrof at sympatico.ca>
> Sent: Sunday, June 28, 2009 8:31:02 PM
> Subject: Re: [s-cars] A Different Brake Light Question
> I would assume you get from 0 to 2 pumps before the pedal is hard
> after the
> car sits? If it takes 30 pumps to deplete the accumulator pressure
> shortly after
> shutdown, then the pump must be supplying pretty good pressure to charge
> the accumulator that well. Then, pressure is bleeding off during the
> period the
> car sits. Have you tried to quantify this time period? I.e., does
> the system
> maintain enough pressure so the brake light is out at restart for 1
> 4 hours? Or, does this brake light not correlate with lack of boost
> When the brake light is on continuously when hot, can you deplete the
> assist pressure by pumping the brakes and get a hard pedal while
> If so, then you have a problem. If the brakes and steering operate
> maybe it is a sensor problem. The sensor of interest is on the brake
> You did not mention fluid appearance or changes but with the work done
> on the system, I have to assume it is fairly new. It does need to be
> clean to
> perform up to specs, and all the banto bolt screens need to be clean
> as well
> as the filter screen in the reservoir neck. The filter screen is
> bright metal, not
> black. That comes from the hoses and pump seals and can severely
> flow and pressure in the system.
> Are there any hydraulic fluid leaks? Even the smallest seep will
> deplete the
> stored pressure as well as make a mess where you can't see new problems.
> > -----Original Message-----
> > Date: Sat, 27 Jun 2009 14:15:58 -0400
> > From: "Fred Munro"
> > Subject: Re: [s-cars] A Different Brake Light Question
> > To: "'Douglas Fifield'" , "'Scarlist'"
> > Message-ID:
> > Content-Type: text/plain; charset="us-ascii"
> > Douglas;
> > If the light doesn't go off and the reservoir is full, it means that
> > the
> > brake assist system isn't coming up to pressure. This could be:
> > 1. bad pump
> > 2. leaking brake servo
> > 3. leaking "bomb" bypass valve
> > It could also be a flaky reservoir level sensor or emergency brake
> > sensor,
> > but that doesn't sound likely from your description of the symptoms.
> > Fred Munro
> > '97 S6
> > -----Original Message-----
> > From: s-car-list-bounces at audifans.com
> > [mailto:s-car-list-bounces at audifans.com] On Behalf Of Douglas Fifield
> > Sent: June 27, 2009 1:40 PM
> > To: Scarlist
> > Subject: [s-cars] A Different Brake Light Question
> > Gents,
> > I also am having brake light problems. Patient is a 95.5 S6 Avant
> > with about 140K miles on the clock.
> > Symptom is a brake light that stays on too long when cold starting and
> > sometimes does not go off at all when engine is fully warmed in hot
> > weather.
> > Pentosin reservoir is full (even a little over) when engine is
> > running. Braking feels normal - no pulsing of the pedal. With engine
> > off, I got about thirty pumps of the pedal before it went hard.
> > I replaced the brake servo two years ago with a new unit.
> > I was leaning toward a bad bomb before doing the pump-down test.
> > What's left? The pump?
> > Looking for wisdom in Minnesota.
> > --
> > Douglas in MN
> > 95.5 Audi S//6 Avant
> > 73 BMW R60/5 mit Toaster Tank
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