CORRECTIVE ACTION Continued
Test for improperly adjusted pilot operated relief and unloading valve. Install test gage in valve gage
port. With engine operating at 1800 rpm, and spade in stowed position, place spade combination
control valve lever in RAISE position and adjust relief valve.
Adjust relief pressure to 19502050 psi (13,44514,135 kPa). For location of valve gage port and
Inspect all hydraulic hoses and connections for visible indication of oil leaks.
Repair leaks or replace hydraulic hose (TM 9-2350-256-20).
10. Test combination control valve. Install pressure gage in test gage port no. 50 at main winch level
winder. Remove hose no. 21A from valve and plug outlet of valve. If no pressure is indicated on gage
when operating hydraulic system, it indicates a faulty combination control valve. For location of test
Notify next higher level maintenance activity or major unit commander.
11. Test control valve. Install pressure gage in combination control valve port no. 7. If no pressure is
established on gage when actuating control valve, but if pressure is established when removing hose
no. 21A from control valve and plugging outlet, it indicates a faulty main winch control valve.
12. Test for hydraulic motor failure. Remove hose no. 47 from rear of hydraulic motor. A large volume of
oil discharged from port when main winch control valve is engaged indicates a faulty motor.
13. Inspect system selector valve lever for improper position.
Place system selector valve lever in MAIN position.
14. Mechanical failure of main winch gear train.
15. Prepare the hydraulic system for operation per TM 9-2350-256-10.
Verify that the APU emergency winch control valve is in NORMAL OPERATION position (TM
16. Main winch will be in low gear.
17. Conduct all hydraulic operations in 1800 rpm or governed engine speed.
TM 9-2350-256-10 states minimum engine speed for winching operations is 1500 rpm.
18. Conduct all hydraulic operation verifications with a hydraulic reservoir temperature of 110120 F
19. Verify main hydraulic pressure in accordance with step 8.
20. If hoist winch, boom, and spade operate properly, proceed to steps 9 thru 14.
This would indicate satisfactory main hydraulic pump operation.