[Stocker]

When you say it's pumping fluid out of the rear of the master cylinder, are you talking about where the plunger is -- where it attaches to the vacuum booster? That's definitely not right and you'll need to replace the master cylinder.

Still seems like you should get some fluid through the lines though, unless they're blocked. A more likely problem is the bleeders are plugged, which is common. If so, just remove them & clear the blockage (probably mud) then screw 'em back in.