TM 55-1730-229-12
AG 320A0-om-000
TO 35C2-3-473-1
TM 1730-12/1
case, while drain plug (14) is
used to drain overflow tube in
gearcase.
(See figure 4-61.)
Inspect.
Inspect drain plugs (11, 14) for proper
(1) Remove drain plugs (11, 14) by
pushing in and turning counterclockwise
installation.
(ccw) to unlock plug.
(See figure 4-61.)
Remove.
b.
(2) Inspect packing (12), and re-
place if damaged.
NOTE
c. Install. Install
drain
plugs
There are two drain plugs. Drain
(11, 14) by pushing in and turning
clockwise (cw) to lock.
plug (11) is used to drain qear-
Section XV. MAINTENANCE OF HYDRAULIC SYSTEM
The hydraulic sys-
pump, and reduces load on engine (since
tem, figure 4-62, consists of:
the pump must maintain a minimum 500
a hy-
psig pressure for self-lubrication).
draulic pump (mounted on engine gear-
case), a hydraulic module, a dual
The hydraulic system must never be op-
manifold, and hydraulic hoses and lines.
erated without sufficient hydraulic
The
fluid, or pump will be damaged.
The hydraulic system provides adjustable
pump receives a low pressure fluid from
high pressure hydraulic power up to
the hydraulic module reservoir and sup-
3,300 psig at 15 gpm to an aircraft.
plies high pressure hydraulic power.
The pump is designed to allow hydraulic
This hydraulic power can be used to
fluid to leak through the bearings for
drive aircraft hydraulic systems, fill
cooling and lubrication. This fluid is
aircraft reservoirs, or flush aircraft
hydraulic systems.
routed from the pump case drain back to
Output pressure to
The pump receives elec-
the aircraft is adjusted by the operator
the reservoir.
trical commands, set by the operator,
at the hydraulic module control panel.
from the hydraulic module control panel
Hydraulic pressure, once set, remains
constant regardless of the flow rate
for an increase or decrease of output
fluid pressure.
demanded by the aircraft (up to the
maximum flow rate of 15 gpm). The hy-
draulic system uses fluid MIL-H-83282,
Module. The hydrau-
b. Hydraulic
or MIL-H-5606.
Fluid MIL-H-83282 is
lic module, figure 4-63, contains all
limited to low temperature of -4OF.
controls (fluid and electrical) for the
hydraulic system. The module contains a
a. Hydraulic Pump. The hydraulic
pump (with pressure compensation con-
nin -gallon reservoir with attachments
trols enclosed) bolts to the engine/
for manual filling, and draining, over-
flow, and removal of moisture from vent
gearcase pump mounting pad.
The pump
air that enters as fluid level changes.
is driven by the enqine/gearcase at ap-
proximately 8,000 rpm.
High pressure (3 micron) and return (10
For units not
micron) filters have throw-away ele-
requiring hydraulic power, a spacer is
The filters have built-in elec-
provided to bolt between the engine/
ments.
trical circuits that illuminate the
gearcase and pump.
This spacer dis-
CHANGE FILTER light on the control panel
connects the pump from the drive gear.
This eliminates unnecessary wear on
when the filter elements need changing.
