JLG sky trak mmv Service Manual page 173

8
5
4. Attach a wire or small-diameter rod to the extend
chain clevis'. The string, wire or rod must be long
enough to pull the clevis' and chains through the
boom. This will be used to pull the new chain
through the boom during installation.
5. Remove the complete extend chains and clevis' as
an assembly from the front of the boom.
6. Inspect wear and condition of the booms, chains,
clevis', chain sheaves, extend/retract cylinder, chain
rods, clevis anchors and all mounting hardware.
Replace any worn or damaged parts. DO NOT
attempt to make any repairs to the chain.
IMPORTANT: Chains and clevis' are wear items and
experience the same stress. DO NOT attempt to service or
repair a chain or clevis. Always replace a stretched or
damaged chain or clevis with a new chain assembly,
which includes the chain and both clevis ends.
Model MMV Rev. 12/04
6
7
MT3090
Extend Chain Installation
1. Assemble the extend chains and anchor hardware.
2. Working at the front of the boom, attach the extend
chain clevis' to the wire or small-diameter rod used
in Step 4 of the removal procedure.
3. From the rear of the outer boom, pull the extend
chains through the boom.
Note: ALWAYS replace elastic locknuts with new elastic
locknuts to help ensure proper fastening.
4. Install the extend chain clevis' into the holes in the
inner boom and install two 3/4" plain washers and two
3/4-16 elastic locknuts (6). Tighten the elastic locknuts
only until the threads of the elastic locknuts are fully
engaged with the clevis'.
5. Install the lower rear wear pads and spacers onto
the inner boom. Coat the intermediate boom wear
pad capscrews with Loctite
5
®
allow Loctite
6. Install the extend/retract cylinder. Refer to Section
4.3.2, b. Inner Boom Installation . Follow Steps 13-22.
7. Check and adjust the boom chain. (Refer to Section
4.3.6, Boom Chains for measurement and adjustment
procedures.)
Retract Chain Removal
1. Removal of the extend/retract cylinder is required to
remove the retract chain. Refer to Section 4.3.2, a.
Inner Boom Removal . Follow Steps 1-24.
Note: Record the mounting hole location of socket-head
shoulder bolt (7), to ensure correct installation.
2. At the rear of the inner boom, remove the socket-head
shoulder bolt (7), two washers, and elastic locknut
securing the retract chain (8) to the anchor on the
inner boom. Disconnect the retract chain.
Boom
®
242 (blue). DO NOT
to come into contact with wear pads.
4.29