All the combination valve is for is to push a piston over to turn the brake lite on to warn the driver if one side looses fluid/pressure
No, that is not all the combination valve does.
The valve that lights up the warning light also closes off the leaky half of the system keeping a firmer pedal than otherwise.
The combination valve also provides metering, proportioning and functions as a splitter.
I'm pretty sure if none of that was needed then none of the factory engineers wouldn't have put it in there, notice how they all did it.
I think I'll listen to the engineers.
