Supercuda: Re-read the last paragraph of my post above.

I'm ASKING someone to correct me if I'm wrong. I'm interested in what you have to say, but not at all interested in your BS attitude. So if you can set that aside for just a few minutes, maybe we can have a good dialogue here.

1. From your post above, it does not sound like I'm confused at all about the pressure differential function on a combination valve. It fires the idiot light on the dash.

2. How does the valve perform the 'hold off function'? Don't read anything into this; I'm not being a jerk. I'm just asking a question. My understanding was that the hold-off function was performed in the master cylinder through the use of springs in the piston?

3. How does the valve perform a metering function, or asked another way, what is the mechanism within the valve that performs this function? I thought the size (diameter) of the wheel cylinder pistons, in effect, performed this function?

4. Proportioning. Fully on board with your comments on 'adjustable proportioning valves'. My understanding of this function (ie: the term 'proportioning') is that, ultimately, a percentage of the full braking power is directed to the front brakes, and the remaining percentage is directed to the rear. For instance, 70% to the fronts and 30% to the rear. Again, my understanding was that this proportioning was performed in the master cylinder? You seem to be saying that if you measured the pressure in the line from the MC to the valve, it would/could be higher than the pressure from the valve to the wheel cylinder or caliper?

5. I had some significant issues with the brakes on a ramcharger that resulted in my buying a set of Snap-on brake pressure testers. I don't recall the PSI at work here, but it is not insignificant (several hundred PSI).

When I've taken combination/proportioning valves apart, I don't recall seeing anything inside that would perform these functions.

That said, I'm literally on the other side of the world from a valve OR a FSM. In a brief synopsis would you review the inside of a valve for me? I'm very interested in this topic, and I hear a lot of BS thrown around on the internet. You sound like you know what you're talking about, and I'm willing to listen.

Incidentally, I don't rely on ignorance to kill people. I use my intellect, skill, experience, and cunning.