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> From: David Powell <firstname.lastname@example.org> - who wrote:
> The first warning light I got on my dash was because of low rack oil in the
> reservoir. I added rack oil. The oil was pushed right out of the resrvoir
> cap within a very short time.
Possibly(?) normal fluid rise & fall when engine goes on and off.
>My brakes are fading like crazy sometimes. Other times they
> feel fine. I never really know what it will be like when I press the pedal.
> I've been doing a lot of two footed braking lately. Once the brakes are
> pumped up they seem to work well. If I don't use them for a few minutes
> they get soft, then very manual. The brake reservoir is full and never
> needs fluid. I recently bled the whole system just to see if it would help.
> The brakes have not been bled in the last 120k miles as far as I know so I
> figured it couldn't hurt. The power steering is working reasonably.
So far, sounds like it might be a pressure accumulator problem.
> got a friend that road trips with me who says the settering is getting
> worse but I don't notice since I drive the car every day. It is by no
> means manual. This leads me to believe the power steering pump (remanufactured
> ZF) is still working.
If the pump failss, you lose power assist for brakes and steering.
That's a fast clue. However - if you feel pulsing thru the steering,
it can (again) point at the pressure accmulator.
> The brakes seem very solid and don't go to the floor
> when the car is off.
Really? Have you tried counting pumps to see when assist drops off?
(I'm not casting the first stone - I STILL can't feel any difference
when the engine is off. I have done this six times and just CANNOT
feel any difference unless the car is moving...so I don't consider
this much of a test unless the car is moving...)
> When the car is running I can force the pedal to the
> floor with the help of the servor. I don't know if this is supposed to
> happen. I reason the brakes would fade with the car off if the master
> cylinder was falty so I don't think it's the master cylinder.
I don't know what to think of this. It does not sound right to me,
as I can't press the pedal to the floor at ANY time, running or not.
> My bentley manuals suggested I remove reservoir return hose from the brake
> servo and see if fluid comes out. None did. I put everything back together
> and pumped up the brakes, then shutdown the car and repeated the test. Fluid
> oozed out slowly. This may indicate a leakly servo but I don't know if it
> is my major problem. On a car this old there may be several things going
Sounds to me like your brake servo is OK. That test is supposed to
> I'm not interested in completely reconditioning the brake system. I
> want to fix the one thing that is causing my power brakes to die completly.
> My bently manual suggests I do a few other tests with a pressure guage. I
> don't have one. I don't want one unless it's cheap. I'll take it to a
> shop if it comes to that. What I'm hoping for here is some educated and
> experienced guesses about which parts may be failing. I have a feeling
> the shop will test my car and tell me they are all shot, replace the works,
> or better yet junk the car.
An Audi tech can stick a pressure gauge in that system and check the
pressure in less than one hour; it's well worth the labor charge. At
this point, my guess is: TA DA! - The pressure accumulator.
You DO have the idea that bleeding the brake system is a totally
separate fluid than the steering/brake servos, right? Remember that
those two systems are separate and use different fluids. I see from
the notation at the end of your post that you understand this...
Keep us posted.
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