PRIMARY HYDRAULIC SYSTEM MAINTENANCE OPERATIONAL CHECK (cont)
If referenced out of one paragraph or volume into another for additional
troubleshooting, upon completion of the task, return to the maintenance
operational check for the original paragraph or volume.
1. Perform visual check of primary hydraulic system with AGPU operating (TM 1-1520-238-PMS). Replace any
leaking component (TM 1-1520-238-23).
a. If hydraulic fluid is leaking from drilled passageway/port on inboard side of primary hydraulic manifold
about one inch below dirty filter indicators, replace indicator packings (TM 1-1520-238-23).
2. If rotors begin to turn when primary hydraulic external power is applied, replace primary hydraulic pump
outlet check valve (TM 1-1520-238-23).
3. Remove external pressurized air and hydraulic (primary) power (TM 1-1520-238-23).
4. Do not close access doors or install access panels until maintenance operational check is completed.
The hydraulic system is pressurized to 3000 psi. Be certain that trapped
hydraulic pressure is released before loosening any connections. Failure to
do so could result in death or serious injury. If injury occurs, get medical
Total primary system fluid volume is 0.75 gallons.
5. Drain primary reservoir to REFILL level if required (TM 1-1520-238-23).
Decal on access door R325 shows proper positioning of selector valve of
hydraulic hand pump.
6. Set hydraulic hand pump selector valve (fig. 721) to INBOARD position.
HAND PUMP HANDLE
Hydraulic Hand Pump Selector Valve