TM 3-6665-302-34
30 Pin
Pillow housing
20
10
31 Roller
Lockwasher
11
32 Retaining ring
Screw
12
Tubing
33 Retaining ring
Pin
13
Tube coupling
34 Washer
24 Cover
35 Connecting rod assembly
Lockwasher
Tubing
36 Diaphragm
Screw
Ball bearing
16
37 Washer
Screw
17
Gear assembly
38 Screw
Catch
18
Guide
Pump unit subassembly
19
Ball bearing
Figure 3-18. Pump assembly, exploded view -Continued
(3) Using figure 319 as a guide, connect
c. If necessary, rock pump assembly (44)
spring rate scale extension (5) to shoulder pin
slightly while pulling it directly away from chas-
(7).
sis assembly (36).
(4) Connect M74 test set PRESSURE
TEST tubing (4) to fluid inlet port (3).
3-25. Installation
a. Dampen the outside of four ports on top of
(5) Connect bellows and pump to M74 test
pump assembly (44) with water.
set PRESSURE PORT.
(6) Turn M74 test set PRESSURE LOCK
b. Position pump assembly (44) so that its
valve fully counterclockwise.
electrical connector and ports are alined with
mating receptacles in the chassis assembly (36).
(7) Alternately squeeze and release bulb of
Press pump assembly (44) into place in chassis
bellows and pump until M74 test set PRESSURE-
assembly (36). Secure pump assembly in posi-
VACUUM GAGE indicates 10 to 12 inches of
tion with two catches (28, fig. 3-18).
water.
(8) Turn PRESSURE LOCK valve fully
in bottom case assembly (2) and secure with
clockwise.
four catches (10).
(9) Attach spring rate scale (6, fig. 3-19)
to spring rate scale extension (5).
3-26. Cover
(10) Slowly move spring (6) in the direc-
tion of arrow (fig. 3-19) while observing PRES-
a. Removal
SURE-VACUUM GAGE.
(1) Remove pump assembly from detector
(11 ) When pressure begins to decrease, spring
unit assembly (para 3-24).
rate scale must indicate 40 to 90 grams.
(2) Remove two screws (26) and lockwash-
(12) If not, spring tension is incorrect. Re-
ers (25) and slide cover (24) from pump unit
place springs (14, fig. 3-18) as described in
subassembly (29 ).
paragraphs b and c below.
(13) Perform M74 test set shutdown proce-
b. Installation.
dures (TM 3-6665-260-14).
(1) Slide cover (24) over end of pump unit
subassembly (29 ) until mounting holes are alined.
b. Removal.
Make sure that tubing (12 and 15) are in slots in
(1) With cover (24, fig. 3-18) removed, dis-
pump until subassembly (29).
connect end of springs (14) from guide (18).
(2) Install two screws (26) and lockwash-
(2) Disconnect springs (14) from terminal
er (25). Tighten screws.
lugs (9).
(3) Install pump assembly in detector unit
assembly (para 3-25).
c. Installation.
(1) Connect replacement springs (14) to
3-27. Springs
terminal lugs (9).
a. Test.
(2) Connect other ends of springs to guide
(1) Remove cover (para 3-26a).
(18).
(2) Position rollers (31, fig. 3-18) so that
(3) Perform spring tension test (a above)
one roller is centered on guide (18) causing
(4) Install cover (para 3-26b).
maximum tubing compression.
