jcb JS 200 Series, Service Manual

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5 - 1
Section F
Transmission
9803/6400
Section F
5 - 1
Issue 1
Motor/Gearbox
Fault Finding
Piston Motor
Fault Possible cause Countermeasure or remedy
1. Motor does not 1. Device other than the piston motor or Check whether or not the specified
run
reduction gear may have malfunctioned. pressurised oil is delivered to the motor
input side and then inspect each device
and repair if necessary.
2. Sliding area of motor is abnormally worn Replace the excessively worn part. Remove
allowing the pressurised oil to escape. scratches and burrs from the surface and
completely clean all parts. Reassemble the
parts.
3. Improper operation resulting from Disassemble and replace the damaged part.
damage of important motor part. In this Completely clean all parts and reassemble.
case, abnormal noise is heard from the
motor itself.
4. Relief valve is activated because the Check the load state and operate the
motor is excessively loaded. machine under a load which matches the
relief pressure.
2. Motor revolution 1.
Oil not supplied to motor at specified Check whether the specified pressurised
speed is rate due to problems in hydraulic pump, oil is delivered to the motor input side
insufficient
pressure control valve, etc. and then inspect each device and
repair if necessary.
2.
Specified revolution speed cannot After disassembly, check for abnormal
be achieved due to reduced wear of the sliding area and repair or
volume efficiency of motor. replace worn parts.
3. Motor revolution 1. Pressurised oil escaping Disassemble and replace excessively
speed varies
through the drain port due to wear worn parts. Completely clean all parts
greatly on the sliding area of the motor. and reassemble them.
Also, revolution speed variation
resulting from wear in the bearing.
2
. Motor load is excessive and the Check the load state and operate the
automatic 2-speed function is working. machine under a load which matches the
automatic 2-speed set pressure.
4. Oil leaks 1. Oil leaks due to damage of the oil seals Replace a broken oil seal or 'O'-ring with a
or 'O'-rings. new one. When inserting the oil seal, be
careful not to damage the lip. Since the safe
working temperature limit of the oil seal
and 'O'-ring is up to 80°C, it is necessary to
take steps to prevent the hydraulic oil
temperature from exceeding 80°C.