© Feb. 2023
54 TB20J Plus Maintenance Manual
BOOM AND PLATFORM ASSEMBLY
Disassembly
• Before disassembling the lift cylinder, rotate
the boom tube to be parallel to the travel direc-
tion of the chassis, and make sure the turnta-
ble is locked (if equipped with a rotary pin,
make sure the rotary pin is locked).
• Before disassembling the lift cylinder, place
solid and reliable rigid brackets under the
counterweight for support, otherwise the ma-
chine may tip over, causing serious personal
injury and machine damage.
• Before loosening or disassembling the hy-
draulic parts (especially the counterbalance
valve on the cylinder), the hydraulic pressure
of all hydraulic lines should be released and
ensure that the hydraulic oil is completely
cooled down.
• Disassemble the hydraulic components
slowly to prevent the hydraulic oil from splash-
ing and injuring people.
1. Raise the boom tube slightly until the lift cylinder is
accessible and can be easily removed.
2. Support the boom tube assembly at its approximate
center position with suitable lifting equipment (with
the lifting capacity not less than 5t/11023lb) to pre-
vent it from falling during disassembly.
3. Mark and disconnect the hydraulic pipelines on the
lift cylinder and collect the hydraulic oil in the pipe-
lines with a suitable vessel. Then seal the pipelines
and ports.
4. Support the two ends of the lift cylinder with suitable
lifting equipment.
5. Remove the retaining ring at the pivot pin #1 con-
necting the lift cylinder with the boom tube, and
knock out the pivot pin #1 with a brass rod and
mallet.
6. Remove the bolt and nut at the pivot pin #2, and
knock out the pivot pin #2 with a brass rod and
mallet.
7. Slowly remove the lift cylinder with the aid of the lift-
ing equipment.
8. Slowly lower the boom tube to stowed position with
the aid of the lifting equipment.
When disassembling the cylinder, take care to
prevent damage caused by the cylinder falling
and impacting, and also prevent the high-
pressure oil leakage due to impacting.
Installation
Follow the reverse order of the disassembly procedures.
Main Boom Assembly
Fig 5 Main boom assembly
Disassembly
• Before disassembling the main boom assem-
bly, rotate the boom tube to be parallel to the
travel direction of the chassis, and make sure
the turntable is locked (if equipped with a ro-
tary pin, make sure the rotary pin is locked).
• Before disassembling the main boom assem-
bly, place solid and reliable rigid brackets
under the counterweight for support, other-
wise the machine may tip over, causing seri-
ous personal injury and machine damage.
1. Make sure to remove the platform assembly, jib
boom assembly and upward leveling cylinder.
2. Raise the boom tube slightly until the lift cylinder is
accessible and the main boom assembly can be
easily removed.
3. Mark and disconnect the harness connections on
the main boom assembly.
4. Mark and disconnect all hydraulic pipelines on the
main boom assembly and collect the hydraulic oil in
the pipelines with a suitable vessel. Then seal the
pipelines and ports.
5. Use suitable lifting equipment (with the lifting
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