Date: 201404
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: B757-200
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Final Approach; Initial Approach
Airspace: Class B ZZZ
ATC / advisory: Tower ZZZ
Aircraft component: Brake System
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Workload
Second reporter function: First Officer; Pilot Flying
Anomaly: Aircraft Equipment Problem Less Severe; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Flight Crew FLC complied w / Automation / Advisory; Flight Crew Landed in Emergency Condition; General Declared Emergency; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: My First Officer was flying [the] approach. Tower directed a go-around at approximately 2;000 FT. When the landing gear was raised we got an EICAS message 'L HYD QTY.' While cleaning up and headed for a downwind I read the QRH quickly and found page 13.2 and it was just informational. I called up the status page during this and found we had .21 on the left system. I told my First Officer (who was still flying) to put the gear down and configure for landing on downwind. We continued on short final with Tower. I told them we may have a hydraulic leak of some kind and to check the runway after we land. On landing roll Tower told us we had a lot of smoke coming from the right main gear. I declared an emergency and took control of the aircraft at taxi speed and cleared the hi-speed holding short of Runway XX. I instructed my First Officer to call Maintenance while we were waiting for Fire Rescue; I told the flight attendants and the passengers to remain seated. Fire Rescue showed up quickly (around a minute) and instructed us to shut down the right engine. On inspection (ARFF) told us we had a hydraulic leak on the right main gear and that there was no fire but they would follow us to the gate. Maintenance said they would come and tow the aircraft to the gate; which they did. I told the flight attendants and passengers what the problem was and we had no worries other than to wait for the tow. We arrived at the gate and Maintenance had already found the leak; it was a loose brake line fitting on the gear. My First Officer did an outstanding job of continuing to fly the approach while I handled the emergency and our crew coordination made everything flow very smooth.  The flight attendants and passengers were kept informed the entire procedure which took about one hour from the declaration of the emergency to arrival at the gate.


Second narrative: [Report narrative contained no additional information]


Synopsis: A B757 main landing gear brake line fitting developed a leak when the gear was raised during Tower commanded go-around; so the crew completed the QRH for the EICAS alert 'L HYD QTY;' declared an emergency and landed uneventfully.