What was found
WHILE ON APPROACH INTO BCT, THE LANDING GEAR WOULD NOT EXTEND WHEN SELECTED DOWN. FLIGHT CREW DECLARED AN EMERGENCY, RAN THE EMERGENCY CHECKLIST AND PNEUMATICALLY LOWERED THE GEAR. CREW ELECTED TO DIVERT TO PBI, DUE TO A MORE FAVORABLE RUNWAY SUITED FOR THEIR EMERGENCY; WHERE THEY LANDED WITHOUT INCIDENT. MAINTENANCE TROUBLESHOT THE ISSUE DOWN TO A FAULTY LANDING GEAR CONTROL MANIFOLD (P/N: 9914637-2). THE MANIFOLD WAS REPLACED WITH AN OVERHAULED UNIT; SYSTEM BLEED, LEAK AND FUNCTIONAL CHECKS WERE NORMAL. THE AIRCRAFT WAS RETURNED TO SERVICE.