2nd gen RX-7. I've got an adjustable brake bias valve, but never removed the stock proportioning valve - now it's time. There are two inputs from the master cylinder, one labeled "F", the other with an arrow. Two outputs, one labeled "F" to the RF caliper and one labeled "R" to the rear.

I've taken one of these proportioning valves apart. There's a sliding "spool" that uncovers an opening to the rear line, with a spring holding it closed. If I've got it figured correctly, pressure from the front overcomes the spring pressure.

I seems like the easiest way to "remove" the proportioning valve is just to gut it - remove the spool and spring. That would turn it into a manifold connecting the four lines. Is it OK to apply "F" line pressure to the "arrow" line, or do I need to separate the front and rear circuits? If so, I expect I need to connect the "arrow" line to the rear.