TM-9-2350-311-20-2
HOWITZER, MEDIUM, SELF-PROPELLED, 155MM; M109A2, M109A3, M109A4 AND M109A5
TECHNICAL MANUAL; UNIT MAINTENANCE MANUAL FOR CAB, ARMAMENT, SIGHTING AND FIRE CONTROL, ELEVATING AND TRAVERSING SYSTEMS AND ASSOCIATED COMPONENTS
DECEMBER 1993
TM-9-2350-311-20-2 - Page 257 of 828
TM 9–2350–311–20–2
Change 2
5–1
CHAPTER 5
MOUNT AND HOWITZER ASSEMBLY
GENERAL
This chapter provides maintenance instructions for the 155MM howitzer cannon and mount. The M109A5 howitzer contains the
M182 mount and the M284 cannon. M109A2/M109A3/M109A4 howitzers contain the M178 mount and the M185 cannon. The
differences between the two configurations are not extensive (para 1–15). Therefore, only specific differences in the overall
configurations shall be noted within maintenance procedures.
CONTENTS
Page
5–1
THRUST COLLAR, BORE EVACUATOR 11578384, AND BORE EVACUATOR
THRUST COLLARS
5–2
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–2
FIRING MECHANISM ASSEMBLY, M35 (M185 CANNON)
5–3
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–3
FIRING MECHANISM ASSEMBLY, M49 (M284 CANNON)
5–5
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–4
FIRING MECHANISM HOUSING
5–8
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–5
FIRING BLOCK ASSEMBLY AND FOLLOWER ASSEMBLY
5–9
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–6
ADJUSTER LEAF SPRING
5–11
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–7
SPINDLE ASSEMBLY
5–14
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–8
BREECHBLOCK ASSEMBLY
5–20
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–9
CARRIER ASSEMBLY
5–21
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–10
TORQUE KEY
5–29
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–11
DAMPER ASSEMBLY
5–31
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–12
OPERATING CAM
5–32
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–13
DUST SHIELD AND VARIABLE RECOIL ACCESS COVER
5–36
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–14
M42 PERISCOPE COVER DOOR
5–40
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–15
M140 ALINEMENT DEVICE MOUNT ACCESS COVER
5–41
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–16
RECUPERATOR COVER
5–42
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–17
BUFFER ASSEMBLY
5–43
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–18
ACCESS COVER (M182 MOUNT)
5–46
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–19
REPLENISHER ACCUMULATOR ASSEMBLY
5–47
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–20
RADAR ANTENNA BRACKET
5–54
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–21
CRADLE AND HOWITZER ACCESS COVERS
5–55
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–22
DIRECT FIRE RANGE PLATE
5–58
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
BUFFER COUNTER
RECOIL ASSEMBLY
OPERATING
CAM
TORQUE KEY
DUST SHIELD AND HOUSING
FOR THE RECOIL ASSEMBLY
VARIABLE RECOIL
ASSEMBLY
FIRING
MECHANISM
ASSEMBLY
BLOCK ASSEMBLY
(FIRING)
ADJUSTER LEAF SPRING
(LOCATED AT BOTTOM)
SPINDLE
ASSEMBLY
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