SkyTrak 8042 Service Manual - Manual (Page 110)

3.49 Model 8042, 10042, 10054 Legacy Rev. 03/04
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 (N) NEUTRAL, place the neutral lock
lever in the (N) NEUTRAL LOCK position, engage
the parking brake switch and raise the boom to a
horizontal (level) position.
2. Fully extend the boom until the extend chain is taut.
Shut 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