During the removal of the jelly jar master cylinder from my 65 manual brake car, I found I cannot remove the push rod coming from the pedal. It seems to be affixed, or locked into the piston of the master cylinder. Don't I need this particular rod for the conversion to a dual cylinder manual disc brake mopar conversion? I would like to start accumulating what I need for the change over. Just need to be clear. Thanks in advance for advice.