TM-9-2320-272-23-4
TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)
TECHNICAL MANUAL; FIELD MAINTENANCE MANUAL; VOLUME 4 OF 5
SEPTEMBER 2012
TM-9-2320-272-23-4 - Page 823 of 1393
REMOVAL
WARNING
All personnel must stand clear during lifting operations. A snapped chain, or shifting or
swinging load, may result in injury to personnel. Failure to comply may result in injury or death
to personnel.
CAUTION
When disconnecting hydraulic lines and hoses, plug all openings to prevent dirt from entering
and causing internal damage to parts.
NOTE
•
Have drainage container ready to catch oil.
•
Use drain pans to retain leaking/draining fluids. Refer to local procedures and plans for
preventing and responding to fluid spills or leaks. Comply with local regulations when
disposing of clean up material and leaked and spilled fluids.
•
Tag hoses for installation.
1.
Disconnect cylinder extension hose (Figure 1, Item 6) and retracting hose (Figure 1, Item 5) from two boom
adapter elbows (Figure 1, Item 4).
2.
Secure inner boom (Figure 1, Item 18) to outer boom (Figure 1, Item 3) with utility chain (Figure 1, Item 2) to
prevent inner boom movement during hoisting operation.
3.
Attach two utility chains (Figure 1, Item 2) to outer boom (Figure 1, Item 3).
4.
Raise outer boom (Figure 1, Item 3) until weight of boom is fully supported and elevating cylinder retaining
pins (Figure 1, Item 17) are free.
5.
Remove two screws (Figure 1, Item 15), lockwashers (Figure 1, Item 16), and retaining pins
(Figure
1,
Item
17) from outer boom (Figure 1, Item 3) and two elevating cylinders (Figure 1, Item 14).
Discard
lockwashers.
WARNING
Before hoisting outer boom away from wrecker, ensure inner boom is properly secured to
outer boom as outlined in Step (2). Failure to comply may result in injury or death to personnel.
6.
Remove grease fittings (Figure 1, Items 7 and 13) from pivot pin (Figure 1, Item 8).
7.
Remove locknut (Figure 1, Item 12), pivot pin (Figure 1, Item 8), two sleeve bearings (Figure 1, Item 10), and
crane sheave (Figure 1, Item 11) from turntable (Figure 1, Item 9). Discard locknut.
8.
Using lifting device (Figure 1, Item 1) and utility chains (Figure 1, Item 2), with assistant guiding movement,
move outer boom (Figure 1, Item 3) off vehicle and onto jack stands.
9.
Remove utility chains from outer boom (Figure 1, Item 3).
TM 9-2320-272-23-4
0686
0686-2
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