50960025/CP0514
66
PRINTED IN U.S.A.
IMPORTANT:
On the three-section boom, on new
machines or when chains have been replaced, it
is necessary to retorque the front double chain
assembly after one hundred (100) hours of oper-
ation. Failure to do so may allow the chains to
become slack, which can result in a chain jumping
off a sheave. If this occurs, it could result in
severe damage to the boom assembly.
On the four-section boom, three chains are on the top
front of the boom. A fourth and fifth chains are acces-
sible from the rear of the boom (see four-section boom
illustration).
Torque the three chains on the front of the four-section
boom to 50 ft.-lbs. (68 Nm). Lubricate with 80W-90
oil.
IMPORTANT:
On the four-section boom, on new
machines or when chains have been replaced, it
is necessary to retorque the front-center single
chain and the front-outer double chains after one
hundred (100) hours of operation. Failure to do so
may allow the chains to become slack, which can
result in a chain jumping off a sheave. If this
occurs, it could result in severe damage to the
boom assembly.
The retract chains on the 2nd intermediate boom and
the inner boom are pre-set at the factory and do not
require adjustment, unless they are replaced.
Inspect the leaf chains for wear. Run the boom out
slowly to inspect. Conditions to look for include:
cracked or broken plates, protruding or turned pins,
and excessive wear. With a steel tape, measure 16 links
of the strand that flexes over the sheaves. If the section
measures 12.375” (314 mm) or more, the chain should
be replaced. DO NOT repair sections of a chain.
Replace the complete chain.
Chain anchors and sheaves also require inspection, for
worn or broken fingers and worn flanges.
After any chain has been replaced, operate under
loaded conditions and re-check the torque. Adjust the
chains per the following procedure: Extend the boom
to its maximum length, then retract the boom slowly
until the chain slack allows the chain to rest on the top
of the boom. Torque the two chains on the front of the
three-section boom to 30 ft.-lbs. (40 Nm) and the three
chains on the front of the four-section boom to 50 ft.-
lbs. (68 Nm). Lubricate with 80W-90 oil.
CHECKING BOOM SLIDE PAD WEAR
AND CLEARANCE
The boom is equipped with special nylon low-friction
slide pads between the telescopic sections
(see
“Typical Slide Pad Detail” illustration)
. These are pre-
greased and initially worn in at the factory. Normally
greasing is not required, except for maintaining a light
film of grease on the pad tracking areas of the boom
sections. An exception would be if a boom section has
been replaced.
Visually check for loose pad bolts. The bolts are
torqued to 30 ft.-lbs. (40 Nm). If the bolts are re-
torqued at any time, Loctite
®
271 (red) thread lock or
equivalent must be re-applied to the bolts.
Typical Slide Pad Detail
Rear Inner
Shim
Pad
Front
Outer
Three-Section Boom Chain Hookup Detail
Inner
Section
Outer
Section
Intermediate
Section
Two Front
Boom Chains
One Rear
Boom Chain
Two Front
Boom Chains
One Rear
Boom Chain
Outer
Section
1st Intermediate
Section
Inner
Section
2nd Intermediate
Section
Four-Section Boom Chain Hookup Detail
One Front
Boom Chain
