SkyTrak 8042 Service Manual - Manual (Page 199)

Boom
3.138 Model 8042, 10042, 10054 Legacy Rev. 03/04
5. Recheck chain tension. (Refer to Section 3.7.3,
“Boom Chain Tension Check.”)
a. Component/Assembly Verification
The inner (7) to secondary intermediate (8) boom
separation should be checked when assembling new
boom sections or chains, or when the rear retract chain
clevis has been moved forward on the anchor plate.
Measure the separation between the secondary
intermediate and inner boom top plates. The distance (9)
should be at least 13.75" (349 mm) and not greater than
14.25" (362 mm) with the boom fully retracted and the
chains properly tensioned. A distance of less than
13.75" (349 mm) could result in interference and cause
damage to boom components.
If the distance is less than 13.75" (349 mm) or greater
than 14.25" (362 mm):
1. Verify that the retract chain clevis (1) is not mounted
in the last hole (5) in the anchor plate (6) .
2. Make sure that the chain system is properly
tensioned. Refer to Section 3.7.3, “Boom Chain
Tension Check,” and Section 3.7.5, “Inner Boom
Chain Tension Adjustment.”
3. To increase the separation distance: Loosen the
retract chain locknut (12) on the bottom of the
primary intermediate boom one or two turns and
tighten the extend chain locknut (11) the same
number of turns. A minimum of one full thread on the
clevis must protrude beyond the elastic collar of the
locknut.
4. To decrease the separation distance: Loosen the
extend chain locknut (11) at the rear of boom one or
two turns and tighten the retract chain locknut (12)
on the bottom of the primary intermediate boom the
same number of turns. A minimum of one full thread
on the clevis must protrude beyond the elastic collar
of the locknut.
Note: If the secondary intermediate to primary
intermediate boom separation distance cannot be
achieved, contact the local Sky Trak distributor or the
JLG Service Department at 1-877-554-5438 or
1-717-485-6657.
MH4070
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OH2870
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