If you just used a 4 way connector you managed to disgard the seperated front and rear hydraulic brake systems and the safety factor that goes with it.
If you are running a single chamber master cylinder you don’t have separate front and rear hydraulic brake systems. That is not the safest brake system for a track car that gets run hard, or even a grocery getter.
For cars that do not have the ‘check brake’ light, it is easy to rig one up.
Install a warning light that is powered when the ignition switch is on. Use a‘proportioning valve’ like shown in the original post. Run the warning light ground wire to the electrical connector on the valve. If there is a large pressure difference between the front and rear brakes, like one side of the system has a leak, the valve will shift making a ground and causing the brake warning light to illuminate.
