TM-9-2350-311-10 M109 Operator's Manual for M109A2, M109A3, M109A4 and M109A5 Download
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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. 3-45