Adding a Matco Remote Reservoir to a Dual Brake System

I'm building a BD-4C and in my somewhat modified brake system, I have two Matco MC-5 Master Cylinders installed on the left side (one for left brake and one for right brake). On the right side, these two MC-5's have a corresponding MC-4 Cylinder. The MC-4 has two ports - one that connects to the remote MC-5, and the other that connects to the brake lock and then to the corresponding wheel brake.

Here is the big question:

I also purchased two reservoirs (https://www.aircraftspruce.com/catal...p?recfer=4740#) from Spruce to hold a greater amount of brake fluid and permit a visual inspection as part of preflight checks. Now, where do these connect to within the brake system? Normally, I'd say they connect to the MC-4 top port, but this is where the MC-5 connects to (the MC-5 does not have a upper port). Is it that the MC-5's would need to be replaced with MC-4's, or should the MC-4's have a tee installed to permit both the new reservoirs and the MC-5 to be connected?

In your current configuration, the pressure output from your MC-5 cylinders in the left seat should go to the "in" (top port) of the MC-4 cylinders on the right side. The pressure "out" (bottom port) from the MC-4 cylinders would go on to the brake lock and slave cylinder.

You really don't need a reservoir added to the MC-5 brake cylinders since they have their own internal reservoir. If you want to use a remote reservoir, you would want to use MC-4 master cylinders for all 4 master cylinders, then the remote reservoir mounted to the top port of the first MC-4 in the serial line of 2 master cylinders to each wheel.

I've installed dual brakes both ways. Either works fine, but as you referenced in your post, the MC-5 master cylinder doesn't provide any visual inspection option for fluid level.

-Cub Builder