Lull 944E-42 Service Manual User Manual download pdf (Page 79)

100

101

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

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Lull 944E-42 Service Manual User Manual Page 79

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