bleeding 02 brake lines

I'm a little frustrated here. My step dad had attempted to change the brakes on the rear end of my mom's 02 V6 stang. I didn't ge a heads up on it till my step dad FUBARed it all up. He couldn't figure out how to get the piston back into the caliber, and decided to open up the bleeder valve.

So, I came in, got everything buttoned back up. I have the rear end bled out, but I can't find the proportioning valve to bleed out, where would I find that at??? Thanks in advance.

i got the rears bled the other day at the caliper, I didn't notice and bleeders at the master cylinder. I didn't have enough time to get to it today, had to help my lil bro move into his new place, but it first in my priorities after i sleep in a bit.