What was found
AIRCRAFT WAS NOT GROUNDED: AFTER GETTING PUSHED BACK OFF THE GATE TRIED TO TAXI OUT IN THEALLEYWAY. AFTER BRINGING THE THRUST UP TO 40% THE AIRCRAFT WOULD NOT MOVE. WE CALLED OPS AND ASKED FOR A TUG TO COME TO TUG US ABOUT 20 FEET TO GET OUT OF THE RUT. HOWEVER THEY WERE UNABLE TO PULL US. MTX CAME AND SAID THE BRAKES MUST BE LOCKED UP SO THEY HAD US THROW DOWN THE GEAR PINS AND BLEED THE HYDRAULICS THEY WERE THEN ABLE TO PUSH US BACK TO THE GATE. ACCOMPLISHED TAXI CHECK AFTER BRAKES WERE BLED BRAKE SYSTEM OPERATES NORMAL. PER AMM 09-20-00.