TM 9-4940-568-34
3-138
3-42. MAIN HYDRAULIC PRESSURE ADJUSTMENT
THIS TASK COVERS:
Adjustment
INITIAL SETUP
Tools
Tool Kit, General Mechanic’s
(Item 67, Appendix F)
Materials/Parts
Lockwasher (4) (Item 45, Appendix E)
Digital multimeter (Item 12, Appendix F)
Equipment Condition
FRS unloaded, (TM 9-4940-568-10).
Adjustment
(1) Remove four screws (1), lockwashers
(2), washers (3) and cover (4) from valve
mounting
brackets (5). Discard
lockwashers.
(2) Remove protective cap (6) and attach
test meter (7) to test port (8).
NOTE
Crane must be in stowed position when
performing this adjustment. Refer to
(TM 9-4940-568-10).
(3) Operate BOOM control lever (9) DOWN.
NOTE
Reading should be 3000 - 3200
psi (20,685 - 22,064 kPa). If
reading is not 3000 - 3200 psi
(20,685 - 22,064 kPa), perform
steps (4) through (7). If reading
is 3000 - 3200 psi (20,685 -
22,064 kPa), perform step (8).
(4) Check pressure reading.
(5) Loosen jam nut (10) and adjust screw
(11) to lower pressure while operating
BOOM control lever (9) DOWN.
(6) Adjust screw (11) to bring pressure up to
3000 - 3200 psi (20,685 - 22,064 kPa).
(7) Tighten jam nut (10).
(8) Check crane for proper operation and
stow crane (TM 9-4940-568-10).
(8) Remove pressure gage (7) and install
protective cap (6).
(9) Install cover (4) on valve mounting
brackets (5) with four washers (3),
lockwashers (2), and screws (1).
END OF TASK
TEST
PORT
BAR SENSOR
(0–1000)
TEST
METER
9
1
4
11
10
5
6
7
8
2
3
