quote:
...The Brass 'Block' you have pictured is NOT a proportioning valve!! It proportions NOTHING!
Gee Marlin, I never said it was. I said it was the shuttle valve.
You can call it what you want - Safety Check, if you wish - but most of us call it the shuttle valve; Ford called it the pressure differential valve. It is a valuable part of the Pantera brake system and should be retained and kept in good, clean operating condition. As you state, it will retain system pressure to one end of the car should the other incur a fluid rupture.
As for the cast iron 'brake equalizer', its purpose IS NOT to provide equal pressure to both front calipers! That would, as you wrote, easily be accomplished by a simple tee fitting, taking the master cylinder pressure to each caliper.
The equalizer was designed to REDUCE the pressure being sent to the front calipers, while keeping full pressure to the rear calipers. That in turn had the effect of boosting the relative effectiveness of the too-small rear calipers. Thus its common name - proportioning valve - in that it altered the pressure proportion between the front and rear calipers. It was attempting to 'equalize' the performance of the front and rear systems so the fronts wouldn't be locking before the rears had even managed to start effectively grabbing. It was an inadequate attempt to correct a brake system that had far too little rear brake performance.
Larry
