(17)
(18)
(19)
(20)
(21)
(22)
(23)
hydraulic
leaks.
(24)
(25)
TM 55-4920-428-13
Reduce hydraulic power supply pressure to 450 psi.
Pull the hydraulic unit SOLENOID valve knob to OPENED. The knob light shall come ON.
Set the LOW PRESS REGULATOR to full INCREASE.
Set the RETURN SHUTOFF VALVE to full OPEN.
Set the RETURN BACK PRESS valve to full OPEN.
Set the CASE VENT LINE PRESS valve to full OPEN.
Turn the hydraulic power supply return needle valve toward the closed direction until the
unit LOW PRESS gage indicates 450 psi. Hold the pressure for 1 minute. There shall be no
Set the hydraulic power supply return needle valve to full OPEN position.
If no additional test are required. perform normal shutdown procedures per para 2-10. In-
stall panel in the case. (Ref para 5-45)
.
5-45. Hydraulic Unit Panel Installation.
The panel weighs about 130 pounds. Be careful when lifting the panel
to avoid personel injury.
a. Carefully lift the panel and position it in the case, tilting it as required to prevent tube damage.
b. Remove the cap from the RETURN hose attachment fitting. Use care to prevent contamination
from entering the system.
c. Install the 12 flat head panel retaining screws.
d. Install the capon the RETURN hose attachment fitting.
e. Secure the case vent hose with the two stowage clamps.
f. If there are no additional requirements, secure SAS manifold 145HS278-11, dial indicator post
145HS278-10, dial indicator 145HS278-9, and equipment listed in para 2-12, as required.
5-46. Final Test.
This test will be accomplished to verify operation of the hydraulic unit after repair. The test is to be
performed after the panel is installed in the case and prior to releasing the unit for operation.
5-47. Test Preparation. The following shall be performed prior to testing.
a. Remove power cable 145GS278-4 from the cover of the electrical unit.
b. Check that the electrical unit power switch is at OFF. Connect the power cable plug to the
POWER receptacle and to a 115-volt 60-Hz power supply. Connect ground wires between the electrical
unit and hydraulic unit ground terminals and a shop ground.
c. Check that the hydraulic unit SOLENOID switch is pushed to CLOSED.
d. Remove cycle motor and solenoid test cable 145GS278-7 from the electrical unit cover.
5-17
