What was found
LEFT HYD QTY LOW EICAS MESSAGE, FOLLOWED BY LT HYD SYS PRESSURE LOW DURING CRUISE FLIGHT, APPROX ONE HOUR PRIOR TO LANDING. AP FOLLOWING QRH PROCEDURES TURNED OFF THE ENGINE HYD PUMP AND LT ELEC HYD PUMP.HYD QTY INDICATED 0.04 ON STATUS PAGE. FOUND HYD FLUID LEAKING FROM L EDP CASE DRAIN PRESSURE FILTER, FURTHER CHECKED AND FOUND THE LT EDP CASE DRAIN PRESSURE FILTER DIFFERENTIAL PRESSURE INDICATOR BROKEN. CHECKED AND FOUND HYD LEAK FROM LT EDP DRAIN TUBE, WHILE REMOVED THE EDP FOUND THE EDP SHAFT WAS BROKEN. R & R THE LT EDP IAW AMM 29-11-05-4-1. R&R THE LEFT SYSTEM RETURN FILTER IAW AMM 29-11-15-4, R & R THE LEFT SYSTEM EDP PRESSURE AND CASE DRAIN FILTER ELEMENT IAW AMM 29-11-17-4, R & R THE LEFT SYSTEM ACMP PRESSURE AND CASE DRAIN FILTER ELEMENT IAW AMM 29-11-18-4. R & R THE DIFFERENTIAL PRESSURE INDICATOR FOR THE LT EDP PRESSURE AND CASE DRAIN FILTER MODULE. PERFORMED A LT ENGINE RUN AT IDLE IAW JRH, CHECKED INDICATOR NORMAL AND NO LEAKING FOUND. PERFORMED L EDP TEST, TESTED NORMAL AND NO LEAKS FOUND, FLUSHED THE LEFT HYD SYS, AND CHECKED ALL REPLACED FILTERS, NO LEAKS FOUND. REMOVED AND REPLACED THE LEFT SYSTEM EDP PRESSURE AND CASE DRAIN FILTER ELEMENT, PERFORMED AN ENGINE RUN AT IDLE IAW JRH, ALL PARAMETES NORMAL. ACFT OK FOR SERVICE.