[s-cars] A Different Brake Light Question

Fred Munro munrof at sympatico.ca
Sat Jun 27 11:15:58 PDT 2009


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


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

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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