Lull 944E-42 Service Manual - Manual (Page 48)

Boom
3-18 944E-42
4. Measure the sag (1) in the top boom extend chain
between the bottom of the chain and the top of the
boom at their closest point. Acceptable boom chain
sag is between 3.0 in (76 mm) and 4.0 in (102 mm).
If the measurement is still less than 3.0 in (76 mm),
the boom chain needs to be adjusted.
If the measurement is either less than, or greater
than the range given, the boom chains need to
be adjusted. Continue with Section 3.4.6, “Boom
Chain Tension Adjustment” to adjust the chain
system.
5. Start the engine, retract the boom completely and
turn the engine OFF.
3.4.6 Boom Chain Tension Adjustment
Note: Always perform Section 3.4.5, “Boom Chain Ten-
sion Check” before adjusting the boom chain tension.
1. Park the machine on a hard, level surface, level the
machine, retract the boom, level the boom, place the
transmission control lever in (N) NEUTRAL, engage
the park brake and shut the engine OFF.
2. Remove the rear boom cover.
3. Adjust the extend chain by tightening or loosening
the retract chain adjustment nut on the front
underside of the first boom section.
4. If the chain sag measurement is less than 3.0 in
(76 mm), the retract chain adjustment nut needs to
be tightened.
If the chain sag measurement is more than 4.0 in
(102 mm), the retract chain adjustment nut needs to
be loosened.
5. Return to the cab, start the engine and cycle the
boom all the way out and all the way in several times.
6. Fully extend the boom, then retract it 2 in (51 mm)
Shut the engine OFF.
7. Measure the sag in the top boom extend chain
between the bottom of the chain and the top of the
second boom section at their closest point.
Acceptable boom sag is between 3.0 in (76 mm) and
4.0 in (102 mm). If the measurement is still less than
3.0 in (76 mm), the boom chain needs to be
readjusted.
Note: If all the adjustment has been used up on the
retract chain adjustment nut and the extend chain is not
within the acceptable sag range, the clevis at the top
front of the first boom section will need to be
repositioned.
8. Return to the cab, start the engine and fully retract
the boom. With the boom horizontal, extend the
boom out approximately 2 ft (610 mm) and shut the
engine OFF.
9. At the front underside of the first boom section,
loosen the retract chain adjustment nut. Back the nut
off until the top of the nut is flush with the end of the
threaded clevis.
10. Return to the cab. Have an assistant watch at the
front underside of the first boom section. Slowly
retract the boom until the retract chain adjustment
nut touches the clevis mounting tab on the underside
of the first boom section.
11. At the front top of the first boom section, move the
extend chain clevis to the next hole toward the rear
of the mounting plates. Coat the mounting pin and
bore hole with anti-seize compound and reinstall the
pin.
12. Return to the cab, start the engine and fully retract
the boom. Shut the engine OFF.
13. At the front underside of the first boom section,
tighten the retract chain adjustment nut to remove
the excess slack from the chains.
14. Make sure that the chain system is properly
tensioned. Refer to Section 3.4.5, “Boom Chain
Tension Check.”
15. Install the rear boom cover.
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