What was found
DURING CRUISE, HYD PUMP TURNED ON & NO MAIN ACCUM PRESS INCREASED. RETURNED TO MIA. FOLLOWED QRH. HYD CWP LIGHT ILLUM. R/R MAIN HYD RES. PERFORMED AIR BLEED SYS AT HYD SYS IAW 29-00-00 OPS & LEAK CHECK SAT. TAXI OUT, HYD PUMP MULTIPLE TIMES PER MINUTE: PRESSURE IN MAIN RES DECREASE FASTER THAN NORMAL. HYD FLUID QTY DID NOT CHANGE. R/R HYD PUMP IAW 29-00-00 OPS & LEAK CHECK SAT. PRESS IN MAIN RES DECREASE FASTER THAN NORMAL, EMERG RES DECREASED. R/R MAIN & EMER ACCUM IAW 29-00-00 OPS & LEAK CHECK SAT. MAIN ACCUM DROPPING PRESS BELOW 2000 PSI PUMP CYCLE 6-8 TIMES DURING TAXI FROM RAMP - RWY. INSPECTED HYD SYS, FOUND HAND PUMP SELECT VALVE OUT OF POSTION. OPS CHECKED ON MAIN ACCUM IAW FAULT ISOLATION 29-10-00-01 PAGE 7 OF MM 29-20-15-04.