Figure 4-1. Panel Lamp, Lens,
and Knob Removal and Replacement
C. Remove lockwire.
d. Unscrew malfunctioned three-way valve (BOOST
SHUTOFF, TRIM SHUTOFF, or SAS SHUTOFF, as
necessary ) from Pilot Assist Hydraulic Module assem-
bly (Figure 4-2 ). Pull up valve and remove from
e. Remove packings
from TRIM SHUTOFF
VALVE, or packings and seals from SAS or BOOST
f. Coat new packings and new seals with hydraulic
fluid (item 3, App D), before installing.
g. If TRIM SHUTOFF VALVE is being replaced,
install new packings on valve. If BOOST or SAS
shutoff valves are being replaced, install new packings
and new seals on valve.
h. Install valve in Module assembly. Install screws.
Torque screws to 19-2 I inch-pounds.
i. Install Iockwire (item 7, App D). Refer to TM 55-
4-14. Pressure Reducer Replacement.
To keep dirt from Pilot Assist Hydraulic
Module assembly, make sure Pilot Assist
Hydraulic Module assembly is clean be-
fore disassembly. Replace pressure re-
ducer only in a clean place. Have re-
placement reducer ready for installation
before malfunctioned reducer is removed.
It is not necessary to remove assembly
from manifold on Test Fixture.
a. Remove lockwire between pressure reducer valve
and thermal relief valve.