MAINTENANCE PROCEDURES
AB18EJ&18HJ Maintenance Manual 5-23 © Oct 2020
Figure 5-21
1. Place the machine in stowed position.
2. Locate the platform rotate motor.
3. Inspect whether the bolt #1 as indicated in the
above figure is properly torqued to specification
(70Nm[52ft-lb]).
4. If necessary, replace the bolt, torque to specified
value, and apply threadlocker Loctite 272.
5. Inspect whether the bolt #2 as indicated in the
above figure is properly torqued to specification
(630Nm[465ft-lb]).
6. If the bolt needs to be replaced, be sure to toruqe to
specifiation.
B-16 Test Cylinder Drift
Platform drift
Measuring the drift from platfrom to ground: with rated
load on platform and power off, fully extend the main
boom. The maximum allowable drift in 10 minutes is
50mm (1.97 in). If the test result exceeds this value,
please proceed as below.
Cylinder drift
Table 5-11
Cylinder Bore
Diameter
（mm/in）
Maximum Allowable Drift in
10 Minutes
（mm/in）
63/2.48 0.96/0.037
80/3.15 0.63/0.025
100/3.94 0.39/0.015
125/4.92 0.23/0.009
160/6.30 0.14/0.006
Cylinder Bore
Diameter
（mm/in）
Maximum Allowable Drift in
10 Minutes
（mm/in）
180/7.09 0.13/0.005
200/7.87 0.10/0.0038
220/8.66 0.08/0.0030
• Measure drift at cylinder rod with a calibrated dial
indicator.
• The oil in cylinder must be at ambient temperature
and consistent.
• The cylinder must be applied with normal load from
the platform.
• The cylinder is acceptable if it passes this test.
NOTE：This information is based on 6 drops per
minute cylinder leakage. Since the hydraulic oil
expands or contracts due to thermal effect, thus the test
value of cylinder drift may have a tolerance of 7/10000.
B-17 Test Oscillate Cylinder Exhausting
and Counterbalance Valve Locking
Testing oscillate cylinder exhausting
NOTICE
Ensure the platform remains in stowed position while
performing the oscillate cylinder exhuasting test.
1. Loosen the hose fitting to the oscillate
counterbalance valve on the left side of machine
until fluid flows out.
2. Place a 120mm (4.7 in)wooden block with bevel
side in front of the front left wheel of the machine.
3. Drive the machine to rest the front left wheel on the
wooden block.
4. During the process, there should be hydraulic oil
and air mixture flowing out of the loosened hose
fitting.
5. Repeatedly drive the machine on and off the
wooden block until there are only hydraulic oil
flowing out of the loosened hose fitting, and then
tighten the hose fitting.
6. Now the left oscillate cylinder exhausts
successfully.
7. Drive the machine off the wooden block.
8. Perform the same procedure to test the exhausting
of oscillate cylinder on the right side.
9. Proceed to test the counterbalance valve locking.
Testing counterbalance valve locking
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