Brake lines/proportioning valve hookup

[Ben Swann]

To cut to the question - read the last line.

I finally got my Willwood Proportioning valve.  I'm pretty sure the old one is
problematic - unable to bleed the system and hear hissing when I activate the pedal and
recall a similar problem on 4000 quattro that had same effect.

So onto installing the new proportioning valve:
http://www.summitracing.com/parts/WIL-260-11179/
This Willwood proportioning valve  has five ports: Rin Rout Fin Fout1 Fout2  
As I understand, Rin is the adjustable proportion circuit controlled by valve to Rout to
be used to adjust bias to the rear brakes.  
The Front in is open - teed to Front outs - no valve.  There is no connection between
the front and rear circuits. 
Nice - simple!

I only thought I'd be using the Rear In and out connections on this unit.  There are
also Front in and two front out, but am not sure how they apply.  So onto the
installation.

As I'm looking at the existing hookup, I realize I don't understand how this works or is
supposed to work.  I referred to ETKA diagram for clarification, but still confused.

It appears there is both front and rear connection from master cylinder to the original
proportioning valve on opposite sides.  I'm not sure exactly what I'm looking at, but
there seems to be a line from the front master cyl.  port as well as one from a rear
port.  Both of these are going into the existing/original proportioning valve - one on
each the two ports on the valve   

The line coming from the rear master cyl. Port also Tees banjo fitting into a line that
goes to the rear . One leg  of the banjo tee at the proportioning valve goes to to the
rear brakes - split by another tee coupler farther back.  ETKA confirms this
configuration.

And there is still  another line coming from the master cylinder - lower rear port which
goes off too the right front according to ETKA - can't really tell by looking, but seems
to be correct.  At first glance I don't see how front brakes can be sharing equal
pressure, but realize pressure is shared within MC and both circuits of the MC provide
pressure to front and rear by this arrangement.

Still seems rather strange way they hooked all this up and not the way I understood
things to be.

So in summary original connections are:

MC Front -> Prop  - only one MC Front port is used other are capped

MC Rear -> Prop and Tee'd	 -> right front 
				->  to rear which is then split again to rear: right and
left
MC Rear - Right Front

I have vague idea that I actually understand what they did and why, but the original
line routing is confusing.

Can someone please explain to me how this works/is supposed to work and how I should
reconfigure to use the Wilwood?

Ben