Service Manual Instruction Manual

SECTION 4 - BOOM & PLATFORM
3121171 – JLG Lift – 4-97
4.30 TOWER BOOM DRIFT TEST
NEVER DIAGNOSE A SUSPECTED TOWER BOOM LIFT CYLINDER DRIFT BY FULLY
ELEVATING THE BOOMS. MACHINE TIPOVER COULD OCCUR.
DO NOT LEAVE THE MACHINE UNATTENDED AT ANY TIME DURING THE TEST.
1. Place the machine on a firm, level surface with an empty
platform, axles completely extended, tires to be ori-
ented straight and both upper and tower booms
retracted and in the transport position. The booms are
to be parallel to the wheels.
NOTE: The machine’s hydraulic oil must be at ambient tempera-
ture prior to starting step 2.
2. Connect the hand held analyzer inside the ground box.
Place the key switch to the ground position. Pull out the
emergency stop switch and start the engine. Using the
analyzer, right arrow to DIAGNOSTICS and press
ENTER . Press the right arrow to get to
BOOM SENSORS and press ENTER . Press the right
arrow until TOWER CYLINDER ANGLE is visible.
3. Using the control operations position the upper and jib
booms at the maximum angle. The telescope cylinder
must be completely retracted. Refer to Figure 4-52.,
Tower Boom Drift Test.
4. Using the ground controls and analyzer display, position
the tower lift cylinder to an angle position between
17.0° and 18.0°. Record tower lift cylinder angle as dis-
played on the analyzer.
5. While still in the DIAGNOSTICS/BOOM SENSORS menu
using the left arrow record the displayed value of
the TOWER ANGLE 1 and TOWER ANGLE 2. Press the
escape button one time, press the left arrow
to SYSTEM and press enter . Record the
CHASSIS TILT angle. NOTE: The displayed value for Tower
Angle #1 and Tower Angle #2 should be between 10.0°
and 12.5° (see Figure 4-52., Tower Boom Drift Test).
6. Visually monitor the tower boom and analyzer display
for drift.
a. After residual boom movement has stopped and all
angle readings listed above have been recorded,
recheck each of the angles on the analyzer to ensure
the values are not currently changing. If immediate
tower boom drift is evident, return the upper boom
to the transport position and then return the tower
boom to the transport position. Discontinue use,
tag the unit out of service and remove key. Contact
JLG service or JLG service provider for diagnosis and
repair information.
b. If tower boom drift is not immediately evident,
record the time at the start of test. Turn key switch
to the off position and depress the emergency stop
switch. Tag unit out of service and remove key.
7. After the unit has remained in this position for 60 min-
utes, pull out the emergency stop switch. Using the ana-
lyzer, right arrow to DIAGNOSTICS and press enter
. Press the right arrow to get to BOOM SEN-
SORS and press enter . Record the TOWER ANGLE1,
TOWER ANGLE 2 and TOWER CYLINDER ANGLE readings.
8. If the angular drift of any of the recorded values exceeds
0.3°, discontinue use, tag the machine out of service and
remove the key. Contact JLG service for diagnosis and
repair information. If the boom drift is less than 0.3°, the
tower lift cylinder is fit for continued service.