The next fault to troubleshoot is the door will not remain in the open
o Shut down the hydraulic system and inspect the hydraulic lines
and fittings for leaks. Repair or replace the line as required.
Start the hydraulic system and open the upper rear door. Close
the flow control valve; if the door does not remain open, replace
the door actuator. Open the flow control valve; if the door does
not remain open, replace the pilot check valve as shown in TM 9-
2350-267-20 (Fig. 61).
The next fault to troubleshoot is the door opens or closes roughly.
o Inspect the hydraulic actuator, oil lines, tubes, fittings, and
hoses for signs of leakage, and repair or replace as required.
o Manually operate the upper rear door directional control valve
with the override buttons located at both ends of the valve (Fig.
51F). If the valve sticks or does not return to center, replace
the directional control valve. If the valve operates correctly
and the upper rear door opens and closes, you must troubleshoot
the electrical system.