TM 10-4320-303-13
5.5.2 Main Valve Assembly Repair. (Continued)
WARNING
Remove cover slowly to release spring tension. Failure to do so may result in personal injury and injury to
personnel.
CAUTION
Pull cover straight up when removing cover from main valve. Failure to do
so may result in damage to cover bearing or valve stem.
b. Slowly lift cover (2) from valve body (3).
c. Remove spring (4) from valve stem (5).
CAUTION
Use vise with soft brass jaws. Failure to do so may result in damage to valve stem.
d. Secure lower end of valve stem (5) in vice with soft jaws.
e. Examine threads on valve stem (5) above stem nut (6) for signs of corrosion or mineral deposits. If
needed, clean threads on valve stem (5) with wire brush before removing stem nut (6).
f. Remove stem nut (6).
g. Remove diaphragm washer (7), diaphragm (8), disc ring retainer (9), and disc ring (10) from valve
stem (5).
h. Pry disc ring (10) from disc ring retainer (9). Remove disc (11) from disc ring retainer (9).
i. Remove disc guide (12) from valve body (3).
5.5.2.2 Repair.
a. Inspect valve stem (5) for corrosion and scale. If required, use sandpaper moistened with water to
clean valve stem (5).
NOTE
If new disc ring is unavailable, flip old disc ring over.
b. Inspect diaphragm (8) and disc (11) for signs of wear, corrosion, and damage.
c. Inspect remaining parts for signs of cracks, holes, wear, corrosion, and damage.
d. Replace all defective components.
5.5.2.3 Assembly.
a. Install disc guide (12) in valve body (3).
b. Install disc ring (10) in disc ring retainer (9).
c. Install disc ring retainer (9), diaphragm (8), and diaphragm washer (7) on valve stem (5).
5-8
