USD caliper sir???
  If so I'd suggest unbolting it from the mount - pushing the pads/pistons right into the caliper and then putting a suitiable block of wood or something between the pads. 
 Then try and get the caliper higher than the master cylinder - pump the pedal a few times, crack the bleed nipple (WITH CARE AS IT MIGHT SPURT!) 
 Repeat until hard......sorry, the brake NOT anything else 
  Cheers - Frank