RE: Wierd brake pedal, A5KCSTQ

["Nicholas C. Craft" <ncc@scr.siemens.com>]

Hi Mark,

I've always found I have to pressure bleed the brakes on our '89 200Q
to stop the pedal staying on the floor.
I'd suggest that first you pressure bleed the brakes and clutch also.
(If you didn't flush & bleed the clutch do it, you'll be amazed at how
nasty the stuff that comes out is). If this doesn't work, the ability to
"pump up" the brake pedal suggests a leaking cylinder, but I
reckon you just need a good pressure bleed.

By the way, I made a pressure bleeder out of a junkyard brake fluid
reservoir cap by drilling it and fitting a tire valve to it. It fits our Audi
and 944, and a Gti also.

I have a compressor but you can use air from a tire etc. if you don't have one.

Good luck,
Nick Craft


-----Original Message-----
From:	MARK DAVISON [SMTP:mark@germanautoparts.com]
Sent:	Friday, August 22, 1997 7:03 AM
To:	quattro@coimbra.ans.net
Subject:	Wierd brake pedal, A5KCSTQ

Hello all:

Hopefully someone can help me with this one. 

The background:

Recently bought an '87 5KCSTQ with ABS.. The braking system was in 
pretty poor condition (warped rotors, siezed rear calipers, bad 
accumulator). In the last few days I have installed new rotors and pads
both front and rear, rebuilt rear calipers, new e-brake cables, new 
accumulator and new master cylinder. I flushed out the system with 
new Ate Typ 200 brake fluid and bled it. 

I do not have a pressure bleeder so I did it with an assistant pumping
the brake pedal with the car running. Open bleeder, pedal down, fluid
out, close bleeder, pedal up, etc. Bled calipers in order per Bentley.

The problem:

Brake pedal travels about 3/5th or 4/5th to the floor before any  braking
occurs and feels a bit spongy even then. BUT, if I depress it that far, let
up until the pedal is almost back to the top and then depress again I have 
excellent  braking at about 1/5th or 2/5th of pedal travel and a firm pedal
as well. Car stops very well then. Repeated immediate releases and 
re-applications give no further change. 

When I let off the brakes completely, wait maybe 10 seconds and
brake again the same thing happens all over again. I have bled the 
brakes 3 times now and have run 2 liters of fluid through with no
bubbles appearing. I was told to try it with the right rear corner jacked
up to level out the valve back there but it made no difference. For what it's 
worth, problems occurs with ABS switched on or off.

Is this just a case of needing a pressure bleeder or is there something
else that I am not aware of? I have used this same method on my
5000S (rear drum, no ABS) with excellent results.

Any suggestions would be greatly appreciated!

Thanks in advance,

Mark Davison
Adirondack Auto Brokers
"Your VW/Porsche Parts Source"
Email: mark@germanautoparts.com
Web Site: www.germanautoparts.com
Phone (518) 882-6534
Fax (518) 882-1914