[V6-12v] Loss of braking power

[David Torrey]

Andrew , Mike -

Mike Knaggs is experiencing the same problem I am having as outlined below.
I think you may be on to something Andrew.  My symptoms feel like there is
no boost assist under hard braking.  The pedal is rock hard but as Mike
says, "one has to stand on the pedal with both feet to stop the car" in a
hurry.  The possibility of a vacuum leak sounds like a strong possibility.
Have you experienced this before Andrew?  Could the brake booster have an
internal leak?

Regards

Dave Torrey


----- Original Message -----
From: "Michael K. Knaggs" <recap at labyrinth.net>
To: "'David Torrey'" <RNE905 at maine.edu>; "Quattro List"
<Quattro at audifans.com>
Cc: "V6 List" <V6-12V at audifans.com>
Sent: Tuesday, April 02, 2002 7:47 AM
Subject: RE: [V6-12v] Loss of braking power


> Dave,
>
> I've got the same problem on my '92 100CSQ.  Do you have an auto or manual
> trans?  Mine is an auto and the problem is evident right away anytime the
> car is warm and I've made a rather quick transition from throttle to
brake.
>  I've also noticed that the brakes feel relatively normal under light
> braking.  But anytime I need to quickly apply more brake, it suddenly
feels
> as though I've lost the power assist from the booster.  I can still brake
> hard at that point but I I need to press very hard with both feet on the
> pedal.
>
> I bought the car last May and have put only 6K on it since then.  The
> problem was evident right away.  I've noticed that the P.O. replaced the
> front pads but the rears were nearly worn out.  The front pads appear to
be
> very hard and make very little dust.  The rears, on the other hand, dust
> like crazy.  I had speculated that my braking problem might be down to a
> missmatched set of pads front and rear.  I had planned to "fix" the
problem
> very soon by replacing rotors and pads with some good performance stuff
and
> also replace the brake fluid and bleed the system.
>
> Now that I've read your posting, though, I'm beginning to doubt that my
> plan to "fix" the problem will work.  Has anyone else on the list had this
> problem?  I know on my old 5KCSTQ a similar problem was fixed by replacing
> the master cylinder.  I wonder if that could be my problem now.
>
> Any advice or first-hand experience is appreciated.
>
> Cheers!
> -Mike Knaggs, '92 100CSQ -Pearl 104K
>
>
> -----Original Message-----
> From: David Torrey [SMTP:RNE905 at maine.edu]
> Sent: Monday, April 01, 2002 4:39 PM
> To: Quattro List
> Cc: V6 List
> Subject: [V6-12v] Loss of braking power
>
> Hi all -
>
> The brakes on my '93 100CSQ Avant aren't what they should be.  When
> braking,
> the car just doesn't seem to exhibit any braking power.  Like there is no
> vacuum boost.  I have tried pumping the brakes with the engine off and
then
> start the engine with my foot on the brake pedal.  The pedal drops when
the
> engine starts.  This is telling me that my booster is working.  Last fall
I
> replaced front and rear pads with stock Pagid's.  Yesterday, I bled the
> brakes and replaced the brake fluid with racing blue.  Still not much
> improvement.  Anyone have any ideas on what I am missing.
>
> Best regards
>
> Dave Torrey
>
>
>
>
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