Machine Does Not Swing - Komatsu Galeo PC138US-8 Shop Manual

40 Troubleshooting
H-20 Machine does not swing
Trouble

• Machine does not swing.

Related
• Conduct the troubleshooting in working mode P.
information
Malfunction of swing holding
1
brake solenoid valve
Possible causes
and standard
Malfunction of swing motor
2
value in normal
(holding brake)
state
3 Swing motor defective
4 Swing machinery defective
Trouble • Machine does not swing.
Related
• Conduct the troubleshooting in working mode P.
information
Malfunction of swing PPC
1
valve
Possible causes
Malfunction of swing control
and standard
2
valve (spool)
value in normal
state
Defective adjustment or mal-
3 function of swing motor
(safety valve)
Defective sealing of swing
4
motor (suction valve)
PC138US, USLC-8
Cause Standard value in normal state/Remarks on troubleshooting
a
Right work equipment control
The holding brake of the swing motor may have a malfunction.
Check it directly.
a
Left work equipment control
The swing machinery may have a defect in it. Check it directly. (It
may be checked by abnormal sound, abnormal heating, metal
chips in drain oil, etc.)
Cause Standard value in normal state/Remarks on troubleshooting
a
Left work equipment control
The spool of the swing control valve may have a malfunction.
Check it directly.
a
Swing lock switch
Sealing of the suction valve of the swing motor may be defective.
Check it directly.
(1) Machine does not swing in either direction.
Keep the engine stopped for the preparations, and keep it
running at high idle during the troubleshooting.
lever
In NEUTRAL
Operated for swing
Keep the engine stopped for the preparations, and keep it
running at high idle during the troubleshooting.
lever
Swing circuit relieved
(2) Machine does not swing in only one direction.
Keep the engine stopped for the preparations, and keep it
running at high idle during the troubleshooting.
lever
In NEUTRAL
Operated for swing
Keep the engine stopped for the preparations, and keep it
running at high idle during the troubleshooting.
Left work equipment
control lever
Swing circuits
ON relieved (separately
on both sides)
SEN02468-01
Solenoid valve output pressure
0 MPa {0 kg/cm }
2
2.84 – 3.43 MPa
{29 – 35 kg/cm }
2
Leakage from swing motor
Below 6 l/min
PPC valve output pressure
0 MPa {0 kg/cm }
2
Above 2.7 MPa
{Above 28 kg/cm }
2
Swing relief pressure
(Pump pressure)
29.2 ± 1.5 MPa
{298 ± 15 kg/cm
1
}
2
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