[s-cars] Brake indicator light

Sun Oct 1 21:14:16 EDT 2006

Mark,

if the fluid is low it is most likely due to a leak in the system
some where. I'd recommend that before changing the fluid you look 
for any signs of fluid leaks.

The reason I advise doing it before is due to the fact that you could
spill some fluid which could make it impossible to determine where
your fluid is leaking.

One common leak point is a plug on the top of the power steering pump
commonly refered to as the " X plug" due to the fact that the head
has an indented X on it for removal/replacement.

Mine was leaking enough fluid that I would go low AND it kept my brake
light on each time I started the car. By replacing this ~ $10 item
it was all fixed.

There is a good write upon this located here:
http://www.elektro.com/~audi/hydraulic/

Good luck

Chris

--- Mark Rivera <mrivera at webcats.net> wrote:

> Alright, more great support from this group.  The problem is surely
> low
> fluid in the PS reservoir.  I notced it just below the "LOW" line
> when I
> picked the car up.  I haven't topped it off, 'cause I haven't been
> able to
> pick up the Pentosin yet.  I'll be changing the brake fluid very soon
> as
> well, and obviously bleeding the system at the same time.  I'll check
> out
> the knowledge base.
> 
> I've been on many helpful automotive lists in the past, and the
> quality of
> info always comes down to the active members who contribute.  You
> guys are
> as good as I've seen, especially to a noob like myself.
> 
> Thanks!
> Mark
> 
> 
> -----Original Message-----
> From: Tom Green [mailto:trgreen at comcast.net]
> Sent: Sunday, October 01, 2006 11:06 AM
> To: s-car-list at audifans.com; mrivera at webcats.net
> Subject: Re:[s-cars] Brake indicator light
> 
> 
> The owners manual describes the conditions that make the BRAKE light
> illuminate,
> some while braking, some without.
> 
> Given the difficulty stopping the car without boost pressure, I think
> they have a note
> about driving under these circumstances.  The annoying light and 3
> chimes really do
> mean "pay attention".   I assume you have plugged the sensors back in
> after testing
> them and cleaning the contacts.  The usual failure mode for the
> sensors is not intermittent
> but a steady failure, and you lose the warning protection if you
> leave them unplugged.
> This system is no smarter than the operator, hopefully less so. :-)
> 
> I agree with Bob's analysis (of course), but thought you would have
> noticed the level in
> the reservoir when unplugging the hydraulic fluid level sensor.
> Perhaps the reservoir is
> too dirty to see the level?   Or, the filter screen insert is
> restricting flow enough to allow the
> float to drop on occasions.  I would only add that the Audi fluid is
> the same as the Pentosin
> 11S, and the price difference is disappearing.
> 
> Let's add an unnecessary note that this Pentosin 11S or Audi power
> steering fluid goes in
> the hydraulic reservoir, and the DOT 4 brake fluid is a separate and
> distinctly different fluid
> that is added to the master cylinder reservoir.  The only commonality
> is they both have level
> sensors that illuminate the BRAKE light when fluid is too low.
> 
> I have seen remarkable improvement from cleaning the hydraulic
> reservoir screen and
> reservoir and flushing and replacing the fluid.  The procedure is in
> the audifans knowledge
> base, except clean the filter screen thoroughly with solvent and
> compressed air.  I don't know
> it's minimum particle size but it is very effective and will restrict
> fluid flow when dirty.  If this
> flushing procedure is too involved or messy, simply emptying the
> reservoir with a turkey
> baster and adding new fluid, drive a few miles and repeat will do
> about the same, just takes
> more fluid, and cleaning the filter twice.   Please dispose of the
> used fluid in an environmentally
> responsible manner.
> 
> Of course, if you have a leak in either the hydraulic boost system or
> the brake system, fix it.
> 
> I offer this as a first step to solving braking problems before
> changing some expensive parts,
> perhaps unnecessarily.  HTH
> 
> Tom
> 
> 
> 
> 
> Mark asks:
> > Date: Sat, 30 Sep 2006 21:01:06 -0400
> > From: "Mark Rivera" <mrivera at webcats.net>
> > Subject: [s-cars] "BRAKE" indicator light
> > To: "S-Car-List" <s-car-list at audifans.com>
> > Message-ID: <KHEHKIJBOCAJPHPCPMNKKEMICLAA.mrivera at webcats.net>
> > Content-Type: text/plain;	charset="iso-8859-1"
> >
> > The "BRAKE" indicator light on my 93' S4 is coming on under medium
> > to heavy
> > braking, but nothing severe enough that ABS comes into play.  It
> > goes out
> > immediately after I release the pedal.  I may have even seen it
> > come on
> > under some corenering situations, not sure.  I've already unplugged
> > the
> > level sensor on the fluid reservoir, as well as the 2 wire sensor
> > around the
> > master cylinder, whatever that one is.  The light still comes on.
> > I should
> > say that the pedal feel isn't that good, and while the brakes work
> > fine
> > under light application, anything more than that requires quite a
> > bit of
> > effort and pedal travel.  In other words, it doesn't feel linear,
> > and feels
> > like the system should be bled.  Is the system smart enough to know
> > that
> > something is wrong, or is the light coming on a different, known
> > issue?
> >
> > Thanks,
> > Mark
> 
> > Bob offers:
> > Date: Sun, 1 Oct 2006 07:57:09 -0400
> > From: "Robert Rossato" <bob.rossato_af at cox.net>
> > Subject: Re: [s-cars] "BRAKE" indicator light
> > To: "'S-Car-List'" <s-car-list at audifans.com>
> > Message-ID: <000c01c6e550$b93ced00$e78ec848 at ROSSATO2>
> > Content-Type: text/plain;	charset="us-ascii"
> >
> > This is most likely a low fluid level in your power steering pump
> > reservoir level.  The sensor on that reservoir is also tied into
> the
> > brake light.  Top it off and I'll bet you the light stops flashing
> > during cornering/braking.  BTDT.
> >
> > You may still have other issues with your brakes, but the brake
> light
> > coming on during cornering or braking is either a low level in the
> > brake
> > fluid reservoir, or the power steering reservoir.  And if you've
> > already
> > checked the master cylinder reservoir, then it's the PS one.  You
> > probably have a small leak at the top X-plug on the pump.  Use
> > Pentosin
> > 11S for the power steering hydraulics.  Don't use anything else.
> >
> > Bob
> 
> 
> 
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