diff between 88 16v rocco and 87 golf 8v master cylinder?

[dan@angband.org (Dan Baisley)]

On Mon, Oct 21, 2002 at 11:46:35AM -0400, broke wrote:
> 
>    I've pulled the 16v unit out of the 88 rocco, and I've compared it to
>    the 20mm unit from my 87 Golf GL. The bolts on the booster match, the
>    thing fits in OK, the only difference I see is the spacing of the
>    lines along the side of the MC....the 16v has more space between each
>    line compared to the 20mm unit.
> 
>    I'm assuming then the 20 and 25 refers to the stroke?

The bore.. but the stock 16v MC has a 22.3 mm bore, and a 17mm primary
stroke and 15mm secondary stroke.   The 25 mm bore MC is used on some Audi
90 and Coupe mnodels.  Using this MC is a downgrade in our brake systems,
you get less hydraulic system pressure per pound of force applied to the
brake pedal, and the additional displacent provided by the 25mm cylinder
is not needed unless you are running dual piston calipers or something
like that. 

>    Anyway, what doesn't match on this MC, or would keep me from using it?

Always used the smallest diameter MC which has enough displacement to run
your brake system.  Rule of thumb, 9.4" calipers use the 20mm, 10.1 uses
the the 22.3.  There is actually one model of 20mm MC which has a longer
stroke and provides ALMOST as much displacement as the stock 16 22.3
MC. (it's somewhere around 2% less displacement.)  I've been meaning to
try that one out sometime...

Dan


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