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 288 of 828

TM 9–2350–311–20–2

5–32

Change 2

5–12 OPERATING CAM

This task covers:

a.

Preparation for Adjustment

b.

Vertical Adjustment

c.

Horizontal Adjustment

d.

Preparation for Service

INITIAL SETUP

Tools

Artillery and turret mechanic’s tool kit

(SC 5180–95–CL–A12)

Fabricated bracket (Figure E–2, Appx E)

5-ton wrecker

Spacer (Figure E–3, Appx E)

Personnel Required

2

Materials/Parts

Cotter pin (item 41, Appx G)

a.

Preparation for Adjustment

WARNING

•

When working on mount and cannon breech components, with cannon pushed out of battery,

block cannon breech with suitable blocking, or chain tube to hull to prevent accidental elevation

of cannon assembly and injury to personnel or damage to equipment.

•

Operators should be in both vehicles while cannon tube is being pushed out of battery. Brakes in

both vehicles must be fully applied during this operation to prevent injury to personnel and avoid

damage to vehicles.

NOTE

Set breechblock mechanism in closed position before beginning procedure.

1

Position howitzer (1) and 5-ton wrecker (2) on level ground.

2

Set cannon tube (3) to zero elevation (TM 9–2350–311–10).

NOTE

Place spacer between shaft collar and recuperator housing.

3

Secure the shaft collar (4) with spacer, remove cotter pin (5) and slotted nut (6) from end of recuperator pis-

ton shouldered shaft (7). Discard cotter pin.

4

Position 5-ton wrecker (2) directly in front of howitzer (1). Aline wrecker boom (8) with cannon tube (3).

5

Install fabricated bracket (9) on wrecker boom (8).

6

Extend wrecker boom (8) to muzzle brake (10). Slowly, push cannon tube (3) out of battery. Push until roller

(11) is positioned opposite arrow (12) on bottom of breech operating cam (13).