Brake light flashing 5kcs

[John Larson]

My car has done this from the day I owned it, and I replaced the accumulator
within a couple of weeks of its purchase because it was completely inop.  As
the light goes out after 15-20 seconds, and brakes work well, I've chosen to
let it go.  I've seen a couple of others with the same problem.  I've been
working on these hydraulclly assistems since about 5 years BEFORE they first
appeared on Audis.  John
----- Original Message -----
From: "Fred Munro" <munrof at sympatico.ca>
To: "John Larson" <j.d.larson at verizon.net>; <mannix at rmsolo.org>;
<quattro at audifans.com>
Sent: Saturday, November 24, 2001 3:07 PM
Subject: Re: Brake light flashing 5kcs


> John;
>
>     The lingering "brake" warning on your 20v is likely due to a leaking
> check valve in the bomb. Check your reservoir Pentosin level just after
you
> shut off the car and check it again in the morning - you'll likely find
the
> level has risen overnight from the fluid leaking out of the bomb back into
> the reservoir. This is also common with the UrS cars - mine does it.
>     Replacing a bomb with passes a 20+ pump test would be rather foolish
> now, wouldn't it? The point I'm making is that before you dive into the
> cheap switches and pump pressure testing, do the bomb test - it's simple,
> free, fast, and if the bomb is over 7 years old, it is quite likely the
> culprit.
>     In this particular case, the additional info about the overflowing
> reservoir points to a pump problem.
>
> Fred Munro
> '94 S4
>
> ----- Original Message -----
> From: "John Larson" <j.d.larson at verizon.net>
> To: "Fred Munro" <munrof at sympatico.ca>; <mannix at rmsolo.org>;
> <quattro at audifans.com>
> Sent: Saturday, November 24, 2001 5:45 PM
> Subject: Re: Brake light flashing 5kcs
>
>
> > I've seen cars with the lingering "Brake" warning even with a new
> > accumulator.  My 20v does this.  Replacing an expensive accumulator that
> > passes the 20+ pump test isn't something I'd even consider.  The
frequency
> > of leaking/failing warning switches is high, and they're cheap.  Without
> > testing the pressures, it's difficult to determine the source of any
brake
> > boost system failure.  In this case, we're not even sure which system is
> the
> > problem.  Is it the brake system or the booster system?  Is it fluid
level
> > or pressure?  With the report of an overflowing reservoir, but also the
> > absence of a sender, is the warning light even related to the boost
> system?
> > John
> > ----- Original Message -----
> > From: "Fred Munro" <munrof at sympatico.ca>
> > To: "John Larson" <j.d.larson at verizon.net>; <mannix at rmsolo.org>;
> > <quattro at audifans.com>
> > Sent: Friday, November 23, 2001 6:39 PM
> > Subject: Re: Brake light flashing 5kcs
> >
> >
> > > Hi John;
> > >
> > >     I had two indications the bomb was dead on my '91 200q. The light
> > stayed
> > > on for over 30 seconds after I started the car (bomb discharged and
> > > repressurizing), and the light flashed under heavy braking (system
> > pressure
> > > too low). The bomb had 3 pumps in it. Replacing the bomb eliminated
the
> > > light issues. The car braked normally, but fortunately I had no
occasion
> > to
> > > stop in a hurry.
> > >      If the bomb is more than 7 years old, I'd tend to suspect the
bomb
> > > before failure of the other components. Without the backup provided by
> the
> > > bomb, it is possible to pull the system pressure down below the
warning
> > trip
> > > for the light with the engine running if you brake hard enough.
> > >
> > > Fred Munro
> > > '94 S4
> >
> >
>
>