Brake pedal to the floor

[Ti Kan]

denis writes:
> My 90 Audi (FWD) brake pedal gone to the floor. The little module attached =
> to the rear swing arm was linky. I replace with one from my old 5000CD. But=
>  the pedale still go to the floor with pooor brake. I have to pump again ev=
> ery 30 sec the keep brake active. And there is NO brake fluide anywhere.
>
> Can i repare the little aluminium module ? 4 brake line go to it.
> Maybe the 5000CD module does not do the same job.

That little module is the brake proportioning valve.  It is not
serviceable and must be replaced if it fails.

> There is no air in the brake sysyem.

How do you know that there is no air in the brake system?  The pedal
sinking to the floor is a classic symptom of air in the brake system.

> Why the brake pedale goes slowly to the floor when i use the brake ?  since=
>  the little module go bad.

If the valve leaks brake fluid, the passage way for fluid to come out
also serves as a way for air to get into the system.  If you replace
the valve, the act of opening up the brake lines will guarantee that
more air gets in.

You need to have your brake system bled of air.

-Ti
2003 A4 1.8T multitronic
2001 S4 biturbo 6-sp
1984 5000S turbo
1980 4000 2.0 5-sp
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