Bleeding Brakes

I have just replaced both of the front calipers and need to bleed the brakes. Granted I know that you're suppose to start at the farthest wheel away from the master cylinder. However, there is no bleeder valve on the driver's side (or at least there's not one located at the wheel itself). I do however see what looks like a larger bleeder valve on a junction box located close to driver's side above the axle.

I read somewhere on the net that someone was having a soft pedal and the tech person told them to bleed the proportioning valve. I'm guessing that's what this thing is I see on the driver's side?

The last time I did any brake work I had my BIL bleed the brakes while I pumped the pedal. I'm hoping someone out there can read this and give me some insite as to what exactly to do.