What was found
(CAN) AFTER DEPARTING, THE FLIGHT EXPERIENCED A YELLOW HYD FAILURE. THE CREW IN CONSULTATION WITH FLIGHT DISPATCH, MTC CONTROL & SOC ELECTED TO DIVERT THE FLIGHT BACK WHERE & OVER WEIGHT LANDING BY 9000 KGS WILL BE CARRIED OUT. THE CREW WILL DECLARE A PAN WITH ATC. RESOLUTION DURING INSPECTION FOUND YELLOW HP MANIFOLD LEAKING FROM CHECK VALVE PN CAR400 O RING`S REPLACED IAW AMM 29-13-53-400-804-A. NO PUMP CAVITATION NOTED.