What was found
(CAN) WHILE ENROUTE FROM YBK TO YTH FAMO EXPERIENCED LOSS OF HYDRAULIC PRESSURE. AN EMERGENCY WAS DECLARED AND THE ACFT DIVERTED TO YTH WHERE AN UNEVENTFUL LANDING WAS MADE. DURING THE FLIGHT HYDRAULIC PRESSURE WAS SEEN TO RISE AND FALL A NR OF TIMES. EMERGENCY U/C ACTUATION WAS NOT REQUIRED. UNDER INSPECTION THE RT HYDRAULIC PUMP WAS FOUND TO BE LEAKING. THE PUMP WAS CHANGED AND THE SYSTEM EXHIBITED NO DEFECTS DURING FUNCTION TESTING. THE PUMP WAS INSPECTED AND THE LEAK WAS FOUND TO BE FROM THE TOP EDGE OF THE END COVER THROUGH A NR OF PIN HOLES IN THE CASTING. THERE WERE NO LEAKS THROUGH THE PUMP FIXTURES AND FITTINGS. THE PUMP WILL BE SENT FOR STRIP EVALUATION.