Swing Acceleration Or Swing Speed Is Low - Komatsu Galeo PC138US-8 Shop Manual

SEN02468-01
H-21 Swing acceleration or swing speed is low
Trouble

• Swing acceleration or swing speed is low.

Related
• Conduct the troubleshooting in working mode P.
information
Malfunction of swing control
1 valve (pressure compensa-
tion valve)
Malfunction of swing motor
2
(holding brake)
Possible causes
and standard
value in normal
state
3 Swing motor defective
4 Swing machinery defective
Trouble • Swing acceleration or swing speed is low.
Related
• Conduct the troubleshooting in working mode P.
information
Malfunction of swing PPC
1
valve
Malfunction of swing control
Possible causes 2
valve (spool)
and standard
value in normal
state
Defective adjustment or mal-
3 function of swing motor
(safety valve)
Defective sealing of swing
4
motor (suction valve)
Malfunction of swing motor
5
(reverse prevention valve)
22
Cause Standard value in normal state/Remarks on troubleshooting
The pressure compensation valve of the swing control valve may
have a malfunction. Check it directly.
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.
Sealing of the reverse prevention valve of the swing motor may be
defective. Check it directly.
(1) Swing acceleration or swing speed is low in both
directions.
Keep the engine stopped for the preparations, and keep it
running at high idle during the troubleshooting.
lever
Swing circuit relieved
(2) Swing acceleration or swing speed is low 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)
40 Troubleshooting
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
PC138US, USLC-8
1
}
2