TM-9-2320-272-10

TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)

TECHNICAL MANUAL; OPERATOR'S MANUAL

SEPTEMBER 2004
CHANGE 2

  TM-9-2320-272-10 - Page 240 of 481

TM 9-2320-272-10
2-139
2-24. OPERATION OF MEDIUM WRECKER (Contd)
(f)
Extend boom (1) to desired operational length by pushing crowd
control lever (4) forward to EXTEND and hoist control lever (3) forward to DOWN.
Maintain even distance between crane block (14) and boom sheaves (13).
(g)
Remove boom jacks (15) from wrecker bed.
(h)
Remove both retaining pins (16) and jack pin (20). Insert jack pin
(20) in hole of 12-ft mark (21) on boom (1).
(i)
Insert boom jack yoke end (17) on jack pin (20) and secure with
retaining pin (16).
(j)
Obtain ring-handled pin (19) and extend boom jacks (15) to required
length. Insert ring-handled pin (19) when required length is obtained and secure
with retaining clip (18).
(k)
Repeat steps i and j on opposite side of boom (1) with second boom
jack (15).
.
WARNING
.
Direct all personnel to stand clear of crane or load during crane
operation. A snapped cable, shifting, or swinging load may
result in injury or death.
(l)
Pull boom control lever (2) to UP position until boom jacks (15) are
off the ground.
(m)
Remove boom jack base plates (12) from wrecker bed.


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