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 723 of 828

TM 9–2350–311–20–2

Change 2

19–15

b.

Service (Method Two)

1

Remove cab access cover if accumulator is installed in cab (para 14–11).

2

Discharge pressure in hydraulic system (para 6–3).

WARNING

Accumulator contains high pressure nitrogen. Use caution when handling and working with it to

avoid injury.

3

Open and close nitrogen cylinder (2) shutoff valve (12) to clear valve seat of any dust or dirt. Repeat this

operation after installation of pressure regulator to clear hose.

4

Connect and tighten nitrogen charging assembly (11) to nitrogen cylinder (2) as shown.

5

Remove accumulator cap (3) and air valve cap (4). Connect air pressure gage assembly (18) to valve body

(6) on accumulator (17).

6

Connect nitrogen charging assembly (11) to air pressure gage assembly (18).

7

Open angle valve (5).

8

Close stop-check valve (9).

9

Close safety-relief valve (19).

10

Open angle valve (20) by turning clockwise.

11

Close pressure regulator valve (14) by turning counterclockwise until no spring pressure is felt.

12

Open nitrogen cylinder (2) shutoff valve (12) slowly until full cylinder pressure is indicated on 4000 psi gage

(13) of pressure indicator.

13

Open pressure regulator valve (14) slowly, turning it clockwise until pressure on 3000 psi gage (15) registers

50 psi (345 kPa).

20

6

17

18

11

12

2

14

13

15

9

5

19

4

3