Breaking my heart

[henry at profitdyne.com]

I Have!. The problem:
Severely contaminated brake fluid and/or deterioration
of the master cylinder return circuit.
To become fully aware of the degree of break drag,
coast the vehicle when approaching a stop in neutral.
at the moment of stop, just before the bounce back let
go at the brake pedal and you will notice the degree of
"whiplash". (if unlocked the car will not kick back).
This condition gets worse when
environmental temperature is greater than 85 degrees
and after driving under normal traffic conditions for
about 8 miles or so.
All four wheels will begin locking the hotter it gets,
so much so that above 95 degrees or so and driving
uphill the "breaking by itself" will become more and
more aggressive. No kidding.
I stopped and Jack the vehicle and all 4 calipers were
locked.
To release it. (don't laugh) pour some cold water over
the master cylinder and all four calipers will begin to
unlock.
No mechanic could believe,diagnose it nor help.
If it was cold outside, the Brake Fluid will not expand
to the point to lock the calipers.
Check the Parking brake mechanism. I did: No change.
Then someone will suggest the ABS, again, no help.
Replace all 4 calipers: Same thing.
It was hell for me.
To find out, Again when it begins to drag, get a rag
and some cold water. pour it over the Master Cylinder
and if it releases you know what to do:

Replace the Master Cylinder and flush the whole system.
Good Luck.
Kindly, Henry.
'91 200 20V quattro wgn, 88 5000Cs quattro wgn.


On Sun, 27 Jul 2003 20:14:24 -0400, Kneale Brownson
wrote:

>
> At 03:15 PM 07/27/2003 -0700, Dr. Adam Gratz wrote:
> >The Machine:
> >
> >1991 200 20V Avant
> >
> >The symptoms:
> >
> >Break pedal becomes resistance free for the first 1/3
> of its travel, and the
> >calipers stay compressed (rear I believe). The brake
> drag is not severe, but
> >is quite noticeable.
> >
> >The last 2/3 of pedal travel feel normal, and the car
> stops well.
> >
> >The symptoms are intermittent, and not relieved by
> disabling the ABS,
> >repeatedly pulling the E-Brake, or repeatedly pumping
> the pedal. The
> >reservoir is full.
> >
> >Differential Diagnosis: ?? Do these symptoms reflect
> any one else's
> >experiences?
>
> Sounds like you have the classic sticky rear caliper
> parking brake lever
> syndrome, Doc.  The fix is to dismantle the caliper
and
> clean all the
> corrosion out of the chamber into which the parking
> brake lever fits.
>
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