TM 5-6115465-34
NAVFAC P-8-625-34
TO 35C2-3-446-2
TM 06858B/06859D-34
(4) Place test stand switch (S2) in the off posi-
(9) Inspect cover and valve block for cracks,
tion to turn off hydraulic fluid pump.
corrosion, and other damage..
(5) Place the actuator unit piston in the full
(10) Check all threads for crossing, stripping,
fuel position and check indication on test stand meter
and peening. Repair minor thread damage with a
thread chaser.
(Ml). Indication should be less than 3 volts.
(11) Inspect top and bottom orifices, spacer for
(6) Place the actuator unit piston in the no
nicks and burrs. Inspect 3 cornered valve for nicks and
fuel position and check indication on test stand meter
burrs on vertical edges that could cause binding depth
(Ml). Indication should be approximately 48-55 volts.
of needle hole should be at least 0.125 inch. Inspection
(7) Slowly, at an even rate, move the hydrau-
bottom face of valve (opposite needle hole) for groov-
lic actuator unit piston from the no fuel to the full
ing. The valve may be polished to remove grooves.
fuel position while observing test stand meter (Ml).
After polishing the bottom face, the overall length of
The indication on meter should decrease; at an even
the valve must be at least 0.240 inch, if not, replace the
rate, from approximately 50 volts to less than 3
volts. The indication should not change directions.
valve.
(12) Inspect needles for burrs and any wear in-
(8) Shut off test stand and remove the hydrau-
lic actuator unit.
dications. Check for straightness by rolling large
diameter end with finger slowly on a known flat sur-
(9) If unit failed to meet test requirements,
face; observe small diameter end while rolling, it must
disassemble and ascertain cause. Retest prior to in-
not move up and down, which indicates a bent needle.
stallation.
A bent needle, new or used, must be replaced as the
pressure at A1 and A2 ports will vary and be difficult
f. Testing without test stand.
to adjust for correct values.
(1) Actuator valve and piston test.
(13) Replace any damaged or defective parts.
(a) See figure 3-38.1 to perform the valve and
piston test.
d. Assembly. Assemble hydraulic actuator unit
in reverse order of disassembly procedures, while
(b) Connect dc power supply (ps) and switch
observing the following:
(S1) to J6 as illustrated. Connect voltmeter (Ml) with
resistor (Rl) to pins A and B of J4.
(1) Install valves (49) with the hole in the up
position to accept needles (46).
(c) Attach gage G1 and G2 as shown. Connect
hydraulic power source (310 -320 psi, 2 gpm) and gage
(2) Transducer body (30) must be installed
G3 and provide a return line from port R to the
0.125 inch below outside edge of valve block. Secure
hydraulic sump.
body with setscrew (25).
(d) TO adjust the valves, remove the large
e. Testing with test stands.
round cover and replace it with a similar diameter collar
which will allow access to the adjustment screws and
(1) Install hydraulic actuator unit in test
jam nuts. This is necessary to contain the hydraulic
stand as follows: (See figure 3-38).
fluid which is ported within this cover.
(a) Connect hydraulic fluid supply from
(e) With hydraulic power but no electric power
test stand gauge (G3) to actuator inlet port (P).
applied, adjust the valve with Allen set screw to yield
200 psi 10 psi at Al port (gage Gl) and 150 psi 10
(b) Connect hydraulic fluid return line to
psi at A2 port (gage G2). (See figure 3-38.1.)
actuator port (R).
(c) Connect test stand gauge (Cl) to
CAUTION: Avoid overadjusting to prevent
actuator unit test point (Al).
pressures or forces which could bend valve push rods.
(d) Connect test stand gauge (G2) to actu-
(f) After adjusting, l o c k Allen adjusting
ator test point (A2).
screws with jam nuts, and install cover.
(e) Connect connectors (P3) and (P4) of
(g) Set S1 to the center position (solenoid coils
test stand electrical cable assemblies to actuator
in series). Apply 350 20 ma through the coils.
unit connectors (J6 and J4) respectively.
Pressures at Al and A2 ports shall remain the same
(step (e) above).
(2) Start the test stand.
(h) Set switch S1 to connect power (PS) to coil
(3) Beginning at position 1, rotate switch (S3)
L2 and apply 700 ma 40 ma. Pressure at Al port
to each position and compare the readings with those
(gage Gl) shall be 310 to 400 psi. Pressure at A2 port
of table 3-2.
(gage G2) shall be 0 to 20 psi.
3-60 Change 3
