Hi, I have just this week done this exact job on by 650z and I had problems bleeding the system, it turned out to be an air lock which I overcame by fixing a transparent tube to the blead nipple tightly, filling the master cylinder reservoir with fluid and then sucking as hard as I could on the tube while I watched the fluid level lower in the reservoir, I stopped sucking when I saw fluid in the transparent tube. I made sure the reservoir was full the whole time. This worked for me I hope something similar works for you.