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 408 of 775

TM 9--2350--311--10

3--8.2

Change 6

3--4

TROUBLESHOOTING — CONTINUED

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

BILGE PUMP

13. BILGE PUMP FAILS TO OPERATE.

Step 1. Check position of BILGE PUMP control switch.

Move BILGE PUMP control switch to ON.

Step 2. Check position of MASTER switch.

Move MASTER switch to ON. If problem persists, notify unit maintenance.

BREECH

14. BREECH DOES NOT CLOSE COMPLETELY.

WARNING

If breech is not closed completely, do not attempt firing, as it may result in death or

injury to crew.

NOTE

Breech is completely closed when witness marks aline.

Step 1. Check to see if breechblock or breech ring threads or components are dirty or burred.

Clean as required. If burrs are present, notify unit maintenance.

Step 2. Check for insufficient lubrication.

Lubricate as required (item 6, Appx G).

Step 3. Check outer edge of spindle assembly and gas check seat for residue or dirt buildup.

Swab areas clean (para 2--13).

Step 4. Check for deformation of the retaining rings and condition of obturator pad.

Disassemble and clean spindle assembly (para 3--6.8). If obturator pad is sliced, cracked, chipped,

or damaged, notify unit maintenance for replacement.

Step 5. Check to see if breech mechanism components are damaged or worn.

Notify unit maintenance if components are damaged.