National Crane Published 08/16/19 Control # 112-05 4-5
500E2 SERVICE MANUAL BOOM
sheaves. Place retract cable ends in a location to
minimize the possibility of damage.
12. Loosen and remove six capscrews securing retract
sheave pin and retract sheaves to 2
nd
section. Remove
sheaves and pins.
13. Loosen and remove two capscrews functioning as upper
retract cable keepers.
14. Loosen and remove two capscrews securing lock bar to
the extend cylinder collar. This bar constrains the
vertical movement of the extend cylinder. Remove bar.
15. Loosen capscrews retaining extend cable anchor to
back of the 3
rd
section. Total removal of the capscrews
will allow the cable anchor to be completely
disassembled, backing capscrews out approximately
0.50 inch (12 mm) will allow the anchor assembly to
slide rearward out of the section as the extend cylinder is
removed.
16. Support extend cylinder with an appropriate lifting
device and pull the extend cylinder out of the boom while
keeping the extend cables and anti-two-block wire
tensioned slightly by hand to minimize the possibility of
damage to the cables. Pull cylinder to within 3 feet (91
cm) of complete removal from the boom sections.
17. Reach into the rear of the 3
rd
section and loosen and
remove the anti-two-block cable clamp on the extend
cable anchor. Pull the extend cable anchor out from its
retaining pocket on the bottom of the 3
rd
section. A slight
angle applied to the anchor as it is being pulled to the
rear will permit easier removal through the 2
nd
section.
18. Remove the extend cylinder from the boom.
a. Do not allow sheaves to fall off the pin on th end of
th extend cylinder.
b. Remove extend cables. Place cylinder and cables in
suitable area to prevent possible damage.
19. Remove retract cables from the back of the 3
rd
section
by manipulating cable end through the slot in the anchor.
Place cables in location to prevent possible damage.
20. Anti-two-block wire can be removed if necessary by
disassembly of the clamp arrangement at the sheave
case and pulling wire through boom.
21. Loosen and remove two capscrews, cable guide, wear
pad and spacer bar from the front top of the second
section.
22. Loosen and remove four capscrews attaching the
bottom pad plate to the second section. Slightly lift third
section, and remove pad plate.
23. Slide 3
rd
section out of 2
nd
section. Removal of side
pads is optional, as the side pads have adequate
clearance for boom disassembly. If removal of side pads
is required, tag all shims, pads and corresponding
locations for proper re-assembly.
24. Loosen and remove all remaining capscrews and wear
pads from boom sections.
Boom Disassembly Alternative #2
The 500E2 Service Manual boom design allows for removal
of the extend cylinder from the rear of the boom without
complete disassembly of the boom sections. This procedure
allows quick access to the cylinder, retract cables, and
various internal boom components for service or
replacement.
1. Remove hoist. Please refer to the hoist removal section
in this book.
2. Gaining access through rear of boom, loosen capscrews
retaining the extend cable anchor in the rear of the 3
rd
section as well as the anti-two-block wire clamp on the
anchor assembly. Loosen and remove two capscrews
retaining lock bar to extend cylinder. Remove lock bar
3. Extend boom 24 inches (61 cm). Loosen and remove
the nuts which secure the extend cables to the cable
anchor plate. Remove nut from anti-two-block spade
bolt.
4. Drape extend cables and anti-two-block wire inside
boom, and slide cable anchor plate out of the side of the
winch mount.
5. Loosen and remove two capscrews, lockwashers and
spacers which anchor the extend cylinder rod butt plate
to the rear of the 1
st
section.
6. Using appropriate lifting device, lift extend cylinder up
and out of retaining slot on rear of 2
nd
section.
Retracting cylinder with an external hydraulic power
source during this step may be necessary.
7. Pull cylinder out through rear of boom assembly
approximately one-half the length of the cylinder.
Turning of the butt plate and rod 90 degrees may aid in
sliding cylinder through winch mount area. Keep extend
cables tight to minimize the possibility of damage.
8. Lift extend cylinder up until it contacts inside of boom
section. Remove anti-two-block wire clamp from extend
cable anchor. Remove anchor by pulling anchor and
cables out rear of boom. A slight angle applied to the
DANGER
Do not, under any circumstances, work at an elevated
height without using proper fall protection as required by
local, state or federal regulations.
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