Replacing clutch master cylinder on 4000Q

[quk@sievers.com (Phil Payne)]

In message <199705301308.AA07488@igw.fmc.com> christopher_bender@fmc.com (CHRISTOPHER BENDER) writes:

>   This guy mentions his problem is that the clutch pedal gets stuck half
>   way down.  Well, I had what I believe to be the same problem, and it
>   has nothing to do with the master cyl.

Betcha.

>   If you look closely at the spring in the clutch pedal, it has what I
>   call an "over center spring" design.   What it does is for most of the
>   travel, it helps you push down on the clutch pedal.  In the final bit
>   of "up travel," the linkage goes "over center," so that the spring
>   helps to push the pedal back up in that last little bit of travel.

Yup.  The German expression is "Uebertotpunktfeder".  It assists the pedal at 
_both_ ends of its travel.  In return mode, the functions of master and slave 
are reversed - the spring in the clutch exerts pressure on the slave cylinder, 
it then exerts hydraulic pressure on the master cylinder, and the master 
cylinder then compresses the "Uebertotpunktfeder" to the point where it pops 
over the dead point and the spring pushes it back into position.
 
This guy's problem is that the master cylinder is not exerting enough force to 
overcome the "Uebertotpunktfeder".  
 
>   What happened with mine is that the hole for the clevis pin in the
>   pedal wore to an egg shape, so that the "push back" from the master
>   cylinder never got the spring to go over center, so the spring was
>   trying to hold the pedal down, and never got to the point where it
>   helps to lift it up.  If I stuck my foot under it and pulled up, thay at
>   would make it "pop" over center, but obviously I didn't want to do
>   that.

They all wear oval.  You probably still have an under-spec master cylinder.  
Can you polish both your shoes?

(Serious question.)

--
 Phil Payne
 phil@sievers.com
 Committee Member, UK Audi [ur-]quattro Owners Club