S4 Problems (long)

[Bfuson@aol.com]

I'm running into two potential problems, and one quirk that I'd like to run
by folks.  The car is a '92 S4, no mods, yet.

First the quirk:  Dash brake light.  I've noticed that after sitting for a
couple of days, if I release the parking brake immediately after starting the
engine, the idiot light stays on for usually 3-5 seconds and then goes out.
 The parking brake isn't binding so I conclude that the light is warning me
about low brake pressure.  

I've gone through three iterations with the dealer on this (I bought the car
used at 48K, now has ~80K miles).  First time I began complaining when this
occurred after the car had set for 6-8 hours.  For my efforts, I received a
new accumulator (bomb), and tightened hoses. That seemed to fix the problem
for about 10K miles, then it began happening again.  Conclusion, the new
accumulator was bad, so I received another one.  I've now put on about 8K
since that happened, and it only occurs after setting for a few days.

None of my other Audi's (86 4K, 91 100, 91 90) have this problem.  As I
understand it, Audi dropped the higher pressure Vickers pump driven system in
92 and went to a lower pressure brake system. Is this a normal side effect,
and one that I shouldn't worry about? In all the instances I've tried the
full pedal in rapid succession test, and have never gotten the light to
flash.

The only good news in this is that: the brakes aren't weak, and all the
repairs were under Audi warranty.  Praise and thanks for small
favors!!!!!!!!!!!!!!!!!

Problem 1:  When driving I hear a noise that sounds like liquid flowing
through a restricted passage.  Sound originally seemed to come from under the
passenger dash, but wasn't very loud.  Now it's back, but louder and seems to
come from the rear of the car.  The sound can't be heard at idle or under
hard acceleration.  Usually hear it at constant speed or when decelerating.
 The sound definitely changes in volume with the gas pedal movement.  It also
occurs in any gear.  Putting it in neutral and increasing engine speed does
not make it reoccur.

The tricky part is that it doesn't always happen. At first I thought about
the fuel pump, but the sound is not metallic or a humming sound (like when I
was loosing the pump on another Audi).

Problem 2.  When going over rough roads I get a thunking sound from the front
suspension.  I can also feel it through the dead pedal when resting my left
foot. I've had the control arm bushings replaced, and had the dealer look at
the suspension components - said he could find nothing loose or unusually
worn. He did retorque the front struts per a TSB.  Maybe of note, this car is
an early S4 and doesn't have the front strut brace.  Steering remains tight
and I don't hear the sound at high speed or on normal (for southern Ohio)
roads.

Could this be struts or strut bearings? I've never had a strut bearing fail,
so I don't know how to recognize a failure.  I know that replacing the struts
on this car is a very expensive undertaking in parts ($300+ each from Audi)
and labor.  Do I have to do the same amount of work to replace a bearing?  Is
this a reasonable do it yourself option?  Is this the time for a suspension
upgrade with non-Audi parts?

TIA,
Bill