80tq: Master Cylinder Revelations

[JShadzi at aol.com]

   Well, since installing the Big Reds, I have been a little unsatisfied with 
the brakes.  I was having trouble really "getting on the brakes" to slow down 
the car.  Locking up the wheels was also no easy feat, and required a lot of 
pedal pressure.  The brakes would work well up to about 75%, but after that 
it almost felt like the brakes would loose power.  
   Stock, the 80 quattro comes with a relaively puney 22mm MC, not bad for 
the original G-54 caliper, but I suspected it was a little lacking for the 
very large Big Reds.  The 25.4mm MC out of a G-60 equipped Coupe Quattro 
looked to bolt right in from the outside (regarding line placement), but 
there were some doubts whether or not the bomb equipped MC would work in a 
vacuum assist car.  Well, after some measurements, I determined that they 
were identical as far as fittament.  
   Last night I installed the 25.4 MC, installed stainless lines in the rear 
(already had them in the front) and pressure bled the whole system with Super 
Blue.  The difference is significant!  I was concerned that with the bigger 
MC, the brakes may be jumpy and hard to modulate, but that is not the case at 
all.  Initially, the pedal is smooth and progressive (about the first .5").  
Give it a harder squeeze and it is quite easy to get the tires into threshold 
traction.  Very easy to control and modulate, minimum amount of travel, very 
firm pedal, I love it.  I finally can get that bulging eye, sick in the chest 
feeling time after time with great modulation and feel.  A highly recommended 
upgrade if you are running any 4 piston caliper such as BIRA, Big Reds, or 
other big piston calipers.
Javad Shadzi