What was found
AIRCRAFT WAS GROUNDED: RANCID ODOR IN CABIN FROM TAKE OFF TO LANDING. MAINTENANCE ISOLATED THE SOURCE OF THE ODOR TO THE APU. MAINTENANCE FOUND HYD FLUID LEAKING FROM AFT BELLY DRAINS, WHICH WAS BEING INGESTED INTO THE APU CAUSING THE ODOR. MAINTENANCE REPLACED THE FORWARD CARGO DOOR HYD SELECTOR VALVE AND THE AFT CARGO DOOR HYD SELECTOR VALVE DUE TO LEAKS BEING NOTED. MAINTENANCE CLEANED THE APU AIR INTAKE IAW TASK CARD 26T31049006, ALONG WITH CLEANING APU COMPARTMENT IAW AMM 49-00-00-100-003-A. THE ENVIRONMENTAL CONTROL SYSTEM WAS DECONTAMINATED IAW TASK CARD 26L00021014 & TASK CARD 26L00021004. A SATISFACTORY LEAK & OPS CHECK ACCOMPLISHED WITH NO LEAKS OR ODORS BEING NOTED.