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 333 of 828

TM 9–2350–311–20–2

Change 2

6–17

c.

Adjustment.

1

Open equilibrator valve knob (4). Leave open approximately 15 seconds, then close.

2

Operate equilibrator hand pump (14) and assistant gunner’s control handle (11), alternating from one to the

other until the howitzer tube raises to maximum elevation.

NOTE

The next step is to ensure equilibration system is not overfilled with hydraulic fluid which will cause

relief valve to open and spill hydraulic fluid at power pack sight gage when cannon is depressed.

3

With cannon tube at maximum elevation, open equilibrator valve knob (4). Leave open approximately 15

seconds, then close.

4

Depress howitzer tube to balance point of +266 mils.

5

Use elevating hand pump (16) to elevate and depress howitzer tube.

NOTE

If possible, use two personnel to perform task to reduce time required.

(a)

If howitzer tube is harder to elevate than depress, increase equilibrator pressure with equilibrator hand

pump (14).

(b)

If howitzer tube is harder to depress than elevate, reduce pressure by draining fluid. Place utility pail

under drain tube (5) and turn open drain valve knob (6).

(c)

Repeat steps (a) and (b) until howitzer tube balances.

6

If required, fill reservoir to FULL AFTER PUMPING mark (12) (para 6–3c.).

4

7

5

6

16

11