Re: 10.1 brake question--The Truth! (long)(er)

[Mash <type53@yahoo.com>]

> > What year and model car?
> 77 Rabbit but basically the same as an MK1 as far as
> stock parts are
> concerned.
===============================
My favorite year for U.S. Rabbits :-)

Not all rabbits even had brake boosters (standard in
all U.S. Sciroccos) - did yours?
> >
> >   I did upgrade to the
> > > bigger master soon after
> > > that and the pedal did seem better but not
> > > dramatically.
> > >
> > > I also disagree with the proportioning valve
> ideas
> > > on the list.  The
> > > proportioning valve restricts the amount of
> > > fluid/pressure going to the rear
> > > so as not to create an out of control rear lock
> up
> > > situation.  On earlier
> > > cars (and some later) they have a level sensing
> > > proportioning valve
> >
> > Some have none - 1975-1980 Sciroccos . . .
> >
> > Are you sure that these are level sensing? My
> Bentley
> > specifically says "This proportioning valve is not
> > load-sensitive and cannot be adjusted" (ignoring
> any
> > Rabbit or Pickup applications).
> 
> I haven't done the upgrade on an MK1 or MK2 (yet
> anyway, I have a MK2 to do
> soon) but my Rabbit had one, the Rabbit pickup had
> one and they are mounted
> to the body with a spring going from a moving arm in
> the level sensor to the
> rear axle.  Couldn't be for anything else!
======================================
Sciroccos don't have this type of item. The Sciroccos
that do have prop valves (1981 & up) have them all
mounted near the master cylinder. 

> >   IF you are doing the upgrade
> > > on a Rabbit, use the
> > > Golf valves, if you are doing it on a scirocco,
> use
> > > the 16v valves.
> >
> > Why the difference? Same chassis, same weight
> > (roughly) . . .
> 
> That is just it, it is 'Roughly' the same weight,
> and in my opinion, isn't
> close enough.

A Rabbit is much closer to a Scirocco in weight than a
(A2) Golf - especially a MK1 Scirocco.

> It is actually irrelevent whether or not you do the
> front disc conversion
> since the prop valves are only on the rear brake
> lines and by limiting the
> amount of press. to the rear so as not to lock up
> the rear brakes does not
> put more pressure to the front brakes.  Prop valves
> are merely to limit the
> pressure to the rear discs to keep them from locking
> up since they actually
> create an uneven bias to the rear.  It is "cool" to
> have the rear discs but
> in all actuality, are unnecessary since this creates
> an overbraking problem.

I would think the purpose of the prop valves is to
eliminate any bias to the rear brakes (locking). I
would also expect that the Scirocco 16V prop valves
take into account the fact that the front brakes have
a much larger swept area, thereby affecting the
forward braking force as compared to the rear. That's
why I'm not sure the Scirocco 16V prop valves are the
ideal solution when keeping 9.4" discs up front.

> Drums are sufficient in most cases and doesn't throw
> brake dust on your
> $2000 wheels

I'll sell you my $2000 wheels for $1000 ;-)

 but they are lower maintenance since
> there is no adjusting and
> no cleaning out the dust from the drums.  I have
> heard that the better
> upgrade for the A1 VWs is the 200mm drums brake
> systems on newer VWs.

Yes, Potterman did this to his 1980 Scirocco some time
ago - he is now running rear disks with A3 calipers.

Thanks Dave - glad you're on this list!



=====
Mark Peele
1985 Scirocco, 1982 Scirocco, 1981 Scirocco, 1978 Scirocco, 1987 Golf GT
http://www.scirocco2.de/mark.htm
Direct Mail: SCIROCCO_GTX@YAHOO.COM
Need parts? try http://www.parts4vws.com/ (Potterman)
or http://www.germanautoparts.com/ (Adirondack)
or http://thescirocco.com

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