What was found
STL - FLT 7431 - FIRST OFFICER'S LEFT BRAKE PEDAL VERY MUSHY, SHOWS NO PRESSURE WHERE FULLY DEPRESSED. MAINTENANCE REFILLED FIRST OFFICER'S BRAKE MASTER CYLINDER, PN ACM26810, BLED BRAKE. TAXI CHECK OF BRAKING SYSTEMS REVEALED NORMAL OPS. AIRCRAFT TT, 10,091.2. (X)