National Crane 600H, Service Manual

Page: 135 / 232

NATIONAL CRANE
08-19-2022 Control # 092-13
4-61
600H SERVICE MANUAL BOOM
4
Sync Cable Adjustment
After all boom sections are assembled, the sync cables can
be adjusted.
1. Fully extend the boom. All sections need to bottom out
on the stops on the bottom of the boom.
The cable clamp bolts for the sync cables should be
lined up with the holes on the side of the boom.
2. The back of the threaded cable stops need to be snug
against the anchors on the top and bottom of the 3
RD
,
2
ND
, and 1
ST
sections.
3. If there is a gap between the back of the threaded cable
stop and the front of the cable anchor, adjust the nut
and/or add spacers to remove the slack.
NOTE: Both the top and bottom cable stops must be
adjusted an equal amount.
4. Torque the cable clamp bolts to 75 lb-ft using the
torquing pattern shown in Figure 4-29 after the cables
are adjusted.
5. Torque the sync cables at both the top and bottom cable
stops using the following sequence.
• Tighten the threaded cable stops to 20 lb-ft on the
bottom of the 1
S T
section, 2
ND
section and 3
R D
section.
• Tighten the threaded cable stops on the top of the
3
RD
section 2
ND
section and 1
ST
section.
• Retract the boom about 2 ft and measure the
following distances
- the distance between the front of the 5
TH
section
and the front of the 4
TH
section.
- the distance between the front of the 4
TH
section
and the front of the 3
RD
section.
- the distance between the front of the 3
RD
section and the front of the 2
ND
section.
- the distance between the front of the 2
ND
section and the front of the 1
ST
section.
• If any distance is greater then the other distances,
tighten the cables until all distances are equal with
the least distance.
FIGURE 4-57
Bolts on the sync
cable clamp
REFERENCE ONLY