What was found
HYDRAULIC LEAK FROM #2 BRAKE LINE. LINE BLEW AT GATE UPON PARKING BRAKE APPLICATION. AFTER PARKING IN PDX, RAMP REPORTED SMOKE FROM #2 SIDE BRAKE. FIRE DEPARTMENT WAS CALLED TO AIRCRAFT. INITIAL EVALUATION INDICATES A LEAKING HYDRAULIC LINE. REMOVED FROM SERVICE. INSPECTED # 3 BRAKE, FOUND #3 BRAKE LINE CHAFFED THROUGH. REMOVED AND REPLACED #3 BRAKE LINE REF AMM TASK 32-42-26-000-801, 32-42-26-400-801. BLED BRAKE AND LEAK CHECK GOOD. NOTE: #2 HYD SYSTEM WAS AT 3.5 QUARTS. CHAPTER 5 INSPECTION NOT REQUIRED. REF AMM TASK 12-10-29-611-801 FOR SERVICING #2 HYD SYSTEM. AIRCRAFT RETURNED TO SERVICE.