JLG 1250AJP Service Manual - Manual (Page 337)

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 DUR-
ING THE TEST.
1. Place the machine on a firm, level surface with an
empty platform, axles completely extended, tires to
be oriented 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 tem-
perature 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 cyl-
inder 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 displayed on the analyzer.
5. While still in the DIAGNOSTICS/BOOM SENSORS
menu using the left arrow record the dis-
played 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 dis-
play 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 evi-
dent, 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 ser-
vice 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 emer-
gency stop switch. Tag unit out of service and
remove key.
7. After the unit has remained in this position for 60
minutes, pull out the emergency stop switch. Using
the analyzer, right arrow to DIAGNOSTICS and
press enter . Press the right arrow to get
to BOOM SENSORS 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 contin-
ued service.