What was found
DURING CLIMB OUT FROM, THE LT AFT BODY O/H LIGHT ILLUMINATED. CHECKLIST- AFT BODY OVERHEAT CARRIED OUT. NR 1 BLEED AND LT PACK TURNED OFF, LIGHT EXTINGUISHED. LT PACK UTILIZED USING NR 2 BLEED, AFTER 3 MIN, NR 2 BLEED AIR HIGH TEMP LIGHT ILLUMINATED. CREW SHUTDOWN ALL BLEEDS, NO CHANGE. CREW SHUTDOWN NR 2 ENGINE, NO CHANGE. FLT CREW DECLARED EMERGENCY AND LANDED, MX FOUND CLAMP AT NR 1 BLEED VALVE BLOWN OFF, NR1 PRECOOLER TO OVERBOARD DUCT CRACKED AND NR 2 - 490 DEGREE O/H SWITCH UNSERVICEABLE. CLAMP WAS REINSTALLED, A SERVICEABLE NR 1 PRECOOLER TO OVERBOARD DUCT (PN 65-58824-9) INSTALLED, A SERVICEABLE NR 2- 490 DEGREE BLEED O/H SWITCH (PN 10-60133-5) REPLACED AND ACFT RETURNED TO SERVICE.