Lull 944E-42, Service Manual

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3.31 Model 644E-42/944E-42 Rev. 6/04
Boom
Other Modes of Failure
• Ultimate Strength Failure - These types of
failures are caused by overloads far in excess of
the design load. Either fractured plates (6) or
enlarged holes (7) can occur. If either of these
failures occurs, the chain must be replaced
immediately. (Refer to Section 3.4.5, “Boom
Extend and Retract Chains Removal and
Replacement.”)
Note: The tight joints inspection must be done with the
chain disconnected from the boom. (Refer to Section
3.4.5, “Boom Extend and Retract Chains Removal and
Replacement.”)
• Tight Joints - All joints in the chain must flex
freely. Tight joints (8) resist flexing and increase
internal friction, thus increasing chain tension
required to lift a given load. Increased tension
accelerates wear and fatigue problems.
If the problem is caused by dirt or foreign substance
packed in the joints, clean and lubricate thoroughly
before re-installing the chain.
If the problem is caused by corrosion and rust or bent
pins, replace the chain. (Refer to Section 3.4.5, “Boom
Extend and Retract Chains Removal and Replacement.”)
b. Expose Extend Chain for Inspection
1. Park the vehicle on level ground. Place the travel
select lever in the (N) NEUTRAL DETENT position,
engage the parking brake and raise the boom to a
horizontal (level) position.
2. Fully extend the boom and turn the engine OFF.
The extend chains will be visible for inspection with the
vehicle in this state.
While doing the chain inspection, check all chain clevis
ends for distortion or cracking and sheaves for bearing
wear or grooving from the chain.
If during the inspection, any chain is found to be damaged
or stretched, the chain must be replaced. It is
recommended that when any chain is replaced, that all
the chains and clevis’ be replaced at the same time.
Note: DO NOT attempt to repair a chain. Replace a
stretched or damaged chain with a new part. Always
replace both the chain and the clevis. It is recommended
that when any chain is replaced, that all the chains and
clevis’ be replaced at the same time.
3. If the chain needs to be replaced, refer to Section
3.4.5, “Boom Extend and Retract Chains Removal
and Replacement.”
4. If the chain does not need to be replaced, lubricate
the chain. (Refer to Section 3.4.2, “Chain
Lubrication.”)
MM2100
MM2110
MM2090
6
7
8