urS4 clutch pressure

[John Larson]

Sorry, I dispute your theory.  The thickness of the disc affects the
geometry of the system, and a thinner disc results in a need for more force
to disengage the clutch.  Your position that it is somehow caused by the
operating system and friction between the bearing and the guide or the
bearing and the clutch cover is indefensible, as the problem appears in
older VWs and Porsches without a guide tube and in Golf/Jetta cars without
the traditional release bearing that contacts the pressure plate.  It's even
evident in those VWs with self adjusting clutch cables.  In nearly EVERY
instance I can remember, complaints of high pedal pressure can be directly
attributed to a thin disc in the long run.  We've frequently replaced badly
worn clutch cables in Golf/Jettas and gone back in very soon to correct the
problem that caused that wear, the worn out clutch.  914s suffer from the
thin disc-high pedal pressure problem to such an extent it tears the clutch
tube right out of the firewall, and require a shim to be placed under the
release arm pivot whenever the flywheel is cut because the new angle of the
arm drastically alters the geometry of the system. John
----- Original Message ----- 
From: "Ado Sigal" <a.sigal at bluewin.ch>
To: "John Larson" <j.d.larson at verizon.net>
Cc: <quattro at audifans.com>
Sent: Tuesday, March 23, 2004 3:51 AM
Subject: Re: RE : urS4 clutch pressure


> Without wanting to offend your experience John, the
> physical fact is, the pressure plate spring rate
> never changes throughout its life, until it brakes,
> so any additional pressure needed on the pedal is
> from the resistance in the transfer mechanism, and
> those two reasons mentioned belong to hydraulically
> operated system.
> Worn clutch plate only reflect itself on the pedal
> point of engagement, worn plate engaging later than
> less worn ones, again, regarding hydro/op method,
> like on most Audi cars. On self adjusting and
> adjustable operated methods, one can't tell the
> state of the plate at all.
> However, my point was that clutch assembly needs to
> get changed on S4 in question, and that should be
> calculated into the price, since it can't be
> remedied without g/box removal, and then it would be
> foolish not to renew everything.
>
> Regards,
>
> Ado
>
> John Larson wrote:
>
> > I'll not get into the whole geometry thing, but I can assure you that
> > increased pedal pressure is indeed a symptom of a thin disc.  Having
done an
> > average of about 2 clutches a month for over 30 years has given me this
> > information, which coincides with established industry opinion.  John
> > ----- Original Message ----- 
> > From: "Ado Sigal" <a.sigal at bluewin.ch>
> > To: "John Larson" <j.d.larson at verizon.net>
> > Cc: <JCassidy at DiamondConstruction.com>; <quattro at audifans.com>
> > Sent: Sunday, March 21, 2004 11:51 AM
> > Subject: Re: RE : urS4 clutch pressure
> >
> >
> >
> >>Its not the worn clutch, but rather dug in thrust
> >>bearing surface and corroded fingers on the pressure
> >>plate that cause heavy clutch. No way to get to it
> >>on S4, so it must be changed. It happens often in
> >>the salt belt aqrea, and cars long standing without
> >>use. Make sure that high temp anti seize compound is
> >>applied to the p/plate fingers and t/bearing contact
> >>surface, when clutch is changed.
> >>
> >>HTH
> >>
> >>Ado
> >>
> >>John Larson wrote:
> >>
> >>
> >>>Worn clutches require noticeably more pedal pressure to get 'em moving.
> >>>
> >>>HTH, John
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> >>>
> >>>
> >>>
> >>
> >>
> >
> >
> >
>
>
>