What was found
SFO INFLIGHT T860 - NOSE LANDING HEAR BOTTOMED OUT ON TAKEOFF ROLL AND COLLAPSED AFTER HITTING A BUMP RISE ON RUNWAY. AFTER GEAR RETRACTION NOSE LANDING GEAR DOORS REMAINED OPEN. GEAR UP RED LIGHT ILLUMINATED. CYCLED GEAR WITH SAME INDICATION. NOSE LANDING GEAR DOORS CONFIRMED OPEN. INSPECTED NOSE STRUT PISTON AND REPLACED NOSE STRUT SCHRADER VALVE O-RING. REPACKED NOSE STRUT. INSPECTED NOSE GEAR DOORS. SYSTEM GROUND CHECKED NORMAL OPERATION.