Table 3-1.—Troubleshooting Flight Hydraulic Power System
Probable Cause
Isolation Procedure
Remedy
STEP 1 TROUBLE: RESERVOIR FLUID LEVEL INDICATOR INDICATES BELOW FULL
Reservoir fluid level low.
Check reservoir fluid level.
Service hydraulic system reservoir.
STEP 2 TROUBLE: FILTER DIFFERENTIAL PRESSURE INDICATOR BUTTON UP
Indicator button not properly
Manually reset indicator button.
Operate hydraulic power system. If
reset.
normal operation results, no further
action required. If indicator button
pops, clean and/or replace filter
element.
STEP 3 TROUBLE: SYSTEM HYDRAULIC PRESSURE FAILS TO DEPLETE
accumulator pressure gauge
Replace gauge with a known
If normal operation results after
defective.
operative gauge.
replacement, use replacement
gauge.
STEP 4 TROUBLE: ACCUMULATOR PRESSURE GAUGE DOES NOT INDICATE 2,000 PSI
Improper accumulator preload.
Deplete hydraulic system pressure,
Service accumulator preload.
then check accumulator pressure
preload.
Air filler valve.
Check air filler valve for leakage.
Retorque swivel nut or replace
defective O-ring, defective filler
valve.
Pneumatic lines.
Check pneumatic lines for leakage. Retorque or replace faulty
pneumatic line section.
accumulator pressure gauge.
Replace gauge with a known
If normal operation results after
operative gauge.
replacement, use replacement
gauge.
accumulator.
Check accumulator for leakage.
Replace defective O-rings or
defective accumulator.
STEP 5 TROUBLE: PILOT’'S HYDRAULIC PRESSURE INDICATOR (UPPER LEFT DIAL) INDICATES
BELOW 3,000 PSI
Hydraulic lines.
Check hydraulic lines for leakage.
Retorque or replace faulty
hydraulic line section.
Pilot’s hydraulic pressure
Replace indicator with a known
If normal operation results after
indicator.
operative indicator. (Refer to
replacement, use replacement
NAVAIR 01-85ADA-2-5.)
indicator.
Pressure transmitter.
Replace transmitter with a known
If normal operation results after
operative transmitter. (Refer to
replacement, use replacement
NAVAIR 01-85ADA-2-5.)
transmitter.
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