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TROUBLESHOOTING
TRAVEL MOTOR
“4. Disassembly and assembly, Travel motor”
Hydraulic motor
Symptoms Major causes Remedies
Motor fails to start •
All the devices other than the motor and the
reduction gears are not working correctly
• Pressure oil is not flowing properly due to ab-
normal wear of the motor’
s sliding part
• Motor is faulty, as its main components are
damaged
•
Check whether the specified pressure
is generated in the inlet port, and then
check and repair each device.
• Replace the abnormally worn out part(s).
• Replace the damaged part(s).
Rated speed cannot be
obtained
•
Specified volume of flow is not supplied to
the motor due to the faulty oil pump
• Motor volume efficiency becomes low
• Check whether the specified pressure
is generated in the inlet port, and then
check and repair each device.
• Check if there is abnormal wear on the
sliding part; if so, repair or replace it.
Rotational fluctuations are
large
•
High-pressure oil is leaking from the drain
port, because the motor’s sliding part is worn
out
•
Bearing is worn out
• Replace the abnormally worn part, if any.
• Replace the abnormally worn part, if any.
Oil leak •
Oil leak due to breakage of oil seal and O-
ring
•
Oil seal is broken by the internal pressure
generated in the motor case due to the ab-
normal wear of the sliding part of the motor
•
Pressure increase in the drain piping caused
by the clogging of foreign matter resulted in
breakage of oil seal
• Replace the oil seal and O-ring.
• Repair the motor and replace the oil
seal.
•
Clean the clogging in the drain piping and
replace the oil seal.
Symptoms Major causes Remedies
Straight-ahead traveling level
is low, switching to 2nd speed
travel is disabled
Spool cannot be switched
•
Foreign matter is caught
• Spring is missing
• Spring is damaged
• Oil leak due to the abnormal wear of
the 2nd speed control piston
• 2nd speed control piston is missing
• Ball is abnormally worn out
• Remove foreign matter and correct or re-
place the faulty part(s).
•
Install the spring.
• Replace the spring.
• Replace the 2nd speed control piston.
• Install the 2nd speed control piston.
• Replace the ball.
2nd speed control
TRAVEL MOTOR
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