Dash 8 First Officer reports #2 hydraulic system failure after a Tower directed go around. Gear is already down and locked when the failure occurs and the crew continues to a normal landing.

Narrative

We were cleared Visual approach. Tower initiated a go-around when the Embraer jet preceding us did not clear the runway in a timely manner. PNF and I commenced go-around maneuver; and proceeded to enter a left traffic pattern in a clean; configuration. The tower cleared us to land again; and we configured the aircraft; gear down; flaps 15; and props 1050 rpm. The #2 RUD ISO caution light illuminated. The #2 HYD QTY gauge showed .5 qts left which confirmed the caution light. We extended our downwind; and the PNF ran the appropriate Emergency/Abnormal Checklist. We had minimal action to take because the gear was showing down 3 green; and the aircraft was already configured. We briefed about the lack of nosewheel steering; as well as limited emergency brake application; and decided declaring an emergency was not appropriate in our situation. We also elected to make a normal landing without informing the flight attendant of the hydraulic malfunction since its impact on our situation was minimal. It was our feeling that spending extra time flying at lower altitude at night while configured was more of a hazard than continuing our traffic pattern to landing and then informing the Flight Attendant once on the ground. The Tower did elect to dispatch the emergency vehicles as a precaution. We landed uneventfully; verified available accumulator pressure for the emergency brake; taxied to the gate; and shut down once the nose wheel was chocked. Upon exterior inspection we did find hydraulic fluid leaking from the #2 landing gear well at the rear portion of the nacelle. Suspected major leak in the #2 hydraulic system when the landing gear was selected down on approach to landing.