I have a 00 honda civic dx, I'm doing a rear disc brake conversion, do i need to change the master cylinder on my car?

I have a 00 honda civic dx, I'm doing a rear disc brake conversion, do i need to change the master cylinder on my car?

Yes, you do.

No. Both types use the same master cylinder.

That's because like on all modern cars the master cylinder operates a split-circuit for safety: one part of the master cylinder piston operates the front left and rear right brakes, the other portion of the piston operates the front right and rear left brakes. That means each half of the piston operates one disc and one drum in your case.

The system is designed that way so that if there's a sudden fluid leak it usually affects only one half of the braking circuit and allows the car to stop safely and in a balanced manner to await recovery.

Yes, AND Delete the Proportioning Valve that you need in a Disc/Drum Layout. In other words… Don't Do it! It has no real advantage. You may stop 1 or 2 feet shorter from 60, so what? Cars are still made with Disc/Drum brakes for one reason: They WORK WELL.