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 171 of 828

TM 9–2350–311–20–2

3–60

3–3

TROUBLESHOOTING — CONTINUED

e.

CAB HYDRAULIC SYSTEM — CONTINUED

2

30

1

24

28

27

29

25

16

23

17

18

22

21

31

34

19

33

9

12

3

15

32

5

6

7

4

8

10

11

13

26

14

20

LEGEND:

1. Rammer blocking valve

2. Rammer actuating valve

3. Rammer assembly

4. Main accumulator

5. Power pack assembly

6. Power valve

7. Pressure regulator

8. Cylinder

9. Pump

10. Pressure gage (2000 psi

(13790 kPa))

11. Pressure switch (925 to 1225

psi (6378 to 8446 kPa))

12. Safety relief valve

13. Reservoir

14. Power relay box assembly

15. Slip ring electrical contact holder

16. ELEVATION CONTROL switch

17. TRAVERSE CONTROL switch

18. CAB POWER switch

19. Traversing mechanism

hydraulic motor

20. Sight gage assembly

21. Right gunner’s control assembly

22. Hydraulic motor bypass valve

assembly motor

23. Left gunner’s control assembly

24. Elevation selector valve

assembly

25. Manual elevating hand pump

26. Shuttle valve and equilibration

manifold assembly

27. Check valve

28. Manual elevation accumulator

29. Elevating cylinder locking

and relief valve

30. Equilibrated elevating cylinder

31. Clutch valve

32. Hydraulic filters

33. Air line filter

34. Hygroscopic breather

OPERATING PRESSURE

900 PSI (6206 kPa)

ELEVATING

SYSTEM POWER

DRAIN RESERVOIR

PRESSURE, 0 PSI

(0 kPa)

PUMP PRESSURE,

925 TO 1225 PSI

(6378–8446 kPa)

ELECTRICAL

CONTROL

CIRCUIT

TRAVERSING

SYSTEM

POWER

CAB HYDRAULIC SYSTEMS (M109A4/M109A5 HOWITZERS)