MAINTENANCE PROCEDURES
TB18 Plus&20J Plus Maintenance Manual 5-27 © Apr 2022
Cylinder Bore
Diameter
(mm/in)
Maximum Allowable Drift in
10 Minutes
(mm/in)
160/6.30 0.14/0.006
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 for each
temperature change of 1℃.
B-17 Test Counterbalance Valve
Locking
NOTICE
After exhausting the oscillate cylinders, test the
counterbalance valve locking, thereafter test the
oscillate system quarterly, or after replacing any
system component, or when any system malfuction
is discovered.
1. Place a 120mm (4.7 in)wooden block with bevel
side in front of the front left wheel of the machine.
2. Extend the boom by at least 1.2m to place the
machine in operating position.
3. Drive the machine to rest the front left wheel on the
wooden block.
4. Slowly rotate the turntble to the right by 90 degrees.
5. The rear detection indicator light will illuminates,
move the function switches to keep the boom
horizontal and fully extended.
6. Inspect the oscillate cylinder, ensure the oscillate
cylinder on the side with load applied is without any
evidence of retracting, and then retract the boom.
7. Move the reverse drive switch to drive the machine
off the wooden block.
8. The assistant on the ground should inspect whether
the wheel on the front left or rear right still remains
off the ground, and keept it elevated.
9. Slowly rotate the turntable to allow the turntable
back to the center position (at the center between
the two drive wheels).
10. Drive the machine forward or reverse, the oscillate
cylinder on the front left wheel should be released
to lower the wheel to come in close contact with the
ground.
11. Perform the same procedure to test the oscillate
cylinder on the front right side.
12. If the oscillate cylinder malfunctions, the malfuction
must be cleared by qualified service technician
before proceeding to next step.
B-18 Inspect Electrical Wiring
Maintaining electrical wiring in good condition is vital to
safe operation and good machine performance.
Continued use of the machine with damaged electrical
wiring or in corrosive environment will lead to unsafe
operation or severe injury. Before operating the
machine, make sure to replace or repair the damaged
or corroded electrical wires.
ELECTROCUTION HAZARD
Before inspecting the electrical
wires, make sure to disconnect the
battery and the charger on the AC
outlet. Contact with hot or live
circuits could result in death or
serious injury.
1. Inspect the electrical wiring in the following areas
for damage or corrosion：
• Engine wiring harness
• Turntable manifold wiring
• Ground controller
• Platform controller
2. Start the engine from the ground controller, and
raise the boom above the turntable.
3. Shut off the engine.
4. Inspect the cable track system for damaged or
corroded power cords.
5. Start the engine from the ground controller, and
lower the boom to stowed position.
6. Shut off the engine.
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