What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED ON APPROACH INTO PHL, AFTER LOWERING GEAR #1 BRAKE TRIPPLE INDICATOR SHOWED 250 LB PRESSURE REMAINING. THE FLIGHT CREW ACCOMPLISHED A GO AROUND TO CONSULT WITH MOC AND TROUBLESHOOT THE ISSUE. IT WAS DETERMINED THAT THE LOW LEVEL RESIDUAL PRESSURE WOULD HAVE MINIMAL TO NO IMPACT ON LANDING AND THE AIRCRAFT LANDED SAFELY AT PHL. FLIGHT CREW REPORTED WITH DIRECT RIGHT CROSSWIND AIRCRAFT PULLED LEFT ON TAXI. MAINTENANCE FOUND THE #1 BRAKE VERY DIFFICULT TO MOVE WITH THE BRAKES OFF AND REPLACED THE #1 MAIN LANDING GEAR BRAKE PER AMM 32-42-27. A SATISFACTORY LEAK / OPERATIONAL CHECK WAS ACCOMPLISHED.