What was found
RT ENG DUCT PRESS FLUCTUATES WITH ENG RUNNING AND BLEED AIR SW ON. SECONDARY INDICATIONS ON CABIN ALT, RATE, AND DIFF GAGES. CREW ELECTED TO DIVERT INTO CVG. LANDING WITH OUT FURTHER INCIDENT. AIRCRAFT WAS GROUNDED BY MAINTENANCE. MAINTENANCE FOUND R/H AIR CYCLE MACHINE HAS LEAK AT AIR BEARING HOUSING. REMOVED AND REPLACED R/H AIR CYCLE MACHINE IAW B767 AMM 21-51-03. OPS CHECK AND LEAK CHECK GOOD. A/C REMAINS ETOPS 180. AIRCRAFT RETURNED TO SERVICE.