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 269 of 828

TM 9–2350–311–20–2

Change 2

5–13

e.

Installation

1

Position adjuster spring (12) and detent plunger (11) in operating crank (6).

2

Insert leaf spring pack (9) and adjuster (8) into operating crank (6) until adjuster is seated.

3

Install setscrew (10) and headless shoulder pin (7).

4

Return cannon assembly to battery. Secure shaft collar (1) with spacer, install and tighten slotted nut (3).

Install new cotter pin (2) on recuperator piston shouldered shaft (4). Remove spacer.

f.

Adjustment

CAUTION

The notches in the adjuster provide graduations of adjustment. Do not apply more pre-load tension

than is necessary to close the breechblock securely at the loading elevation (less than 300 mils).

Use of final notch setting reduces the life of the leaf springs and should be used only if necessary (if

breech does not close at loading elevation).

NOTE

•

There are two types of adjusters. Some have holes for a spanner wrench. Others have lugs for

an adjustable wrench.

•

Adjuster may have only two graduations.

Depress detent plunger (11) and apply pre-load tension on breech mechanism closing springs by turning

adjuster (8) clockwise.

2

4

3

6

7

1

SPACER