Am I right in believing that the proportioning valve in the engine bay will block off the front/rear braking system in the event of a line failure?

It's not going on my XJ but with all the work I'm putting into this, and the lack of impact zones, I'd rather have a back-up just in case.

 

The XJ Valve will allow unimpeded flow to the rear circuit in the event of a front failure; basically bypassing the circuitry. The front already has unimpeded flow. It does not in any way block off a failed circuit. Good pictures:

https://comancheclub.com/topic/47993...ioning-valves/

Continuing the conversation, I'd love an explanation how the components in the 2nd picture of the above constitutes a "proportioning valve". I believe it's a metering valve, requiring pressure to exceed a certain point before allowing it to pass.

 

Thanks Jim. So it's not quite what I'm after then and may not be the best to use. There's no servo assistance so I wonder if it may reduce my rear braking in this use, especially with it being much lighter on the front than the rear.