TM-9-2350-311-10

HOWITZER, MEDIUM, SELF-PROPELLED, 155MM; M109A2, M109A3, M109A4 AND M109A5

TECHNICAL MANUAL; OPERATOR’S MANUAL

NOVEMBER 1994

TM-9-2350-311-10 - Page 445 of 775

TM 9-2350-311-10

3-6

ARMAMENT AND CAB MAINTENANCE — CONTINUED

3-6.4

Zero Pressure Check and Checking, Filling, and Draining Power Pack

Procedure

The zero pressure check should be performed by unit maintenance personnel or when troubleshooting the cab

hydraulic system. The zero pressure check is not performed by the crew as a part of daily or pre-fire preventive

maintenance checks. However, in the event no unit maintenance personnel are available, then it would become the

responsibility of the chief of section and the crew.

The zero pressure check indicates the amount of precharged nitrogen in the main accumulator assembly and if there is

enough hydraulic fluid in the power pack assembly.

It maybe necessary to perform a zero pressure check if the cab traversing, elevation, and rammer systems function

sluggishly or unusually after the before-operation and maintenance checks have been performed.

NOTE

Don’t perform the following procedure unless instructed by chief of section.

1

Position weapon on level ground if possible.

2

Turn MASTER switch (1) and CAB POWER switch (2) to ON to charge system.

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