[s-cars] RE: S6 brake light

[Fred Munro]

Hi Dennis;

The return line you are removing is the return line from the brake servo to
the reservoir. When you apply the brakes, the fluid stored under pressure in
the bomb flows through the brake servo into the reservoir, generating brake
assist in the servo. When the brakes aren't applied, no fluid should pass
through the servo. If it is passing through the servo, the bomb pressure
will eventually bleed off and bingo! - red light on start-up.
Removing the return line from the servo while the bomb is charged will
reveal whether fluid is leaking through the servo.
As the Bentley says, "occasional drops are OK". The servo is above reservoir
level, so fluid will not drain back from the reservoir.

CAUTION!!! IF YOU REMOVE THE SERVO FEED LINE INSTEAD OF THE RETURN LINE, YOU
WILL RELEASE 2000 PSIG OIL FROM THE BOMB WITH PROBABLE DETRIMENTAL EFFECTS
TO YOUR HEALTH, EYESIGHT, AND GENERAL MENTAL WELL-BEING, SO MAKE SURE YOU
KNOW WHAT YOU ARE DOING!!!

This test is more difficult on the UrS cars as the servo return is hard
piped. A rubber hose was used on the Type 44, making the test easier.

If the servo is leaking, it has to be replaced. Flushing the Pentosin may
clean it out and fix it - it's worth a try as a cheap fix.

HTH

Fred Munro



-----Original Message-----
From: DGraber460 at aol.com [mailto:DGraber460 at aol.com]
Sent: June 6, 2003 9:55 AM
To: munrof at sympatico.ca
Cc: s-car-list at audifans.com
Subject: S6 brake light


Fred Munro recently posted the procedure for diagnosing the brake light
issue common for S6's.
I checked the bomb which gave 41 pumps. Good.
Step 2 is to remove the return line to the reservoir. Both lines appear to
be "immersed" in oil. Which is the return, and won't removing it drain the
tank, and issue far more than a "few drops"?
Step 3 showed that the tank level did go up after setting after shut down.
Any advice appreciated. TIA
PS I'm new to the S6 list, so I will probably ask some newbie questions.
Like what's a good source for 95 S6 relevant Bentley data.

Dennis
Denver