Large Shock Is Made When Upper Structure Stops Swinging - Komatsu Galeo PC800-8 Shop Manual

40 Troubleshooting
H-26 Large shock is made when upper structure stops swinging
Failure • Large shock is made when upper structure
phenomenon stops swinging
Relative • When carrying out the following troubleshooting, set the working mode in the P-mode and turn the
information swing lock switch OFF.
Malfunction of swing hold-
1
ing brake solenoid valve
Malfunction of swing motor
2
(parking brake)
Possible causes
and standard
value in normal
state
Wrong adjustment or mal-
3 function of swing motor
(safety valve)
Swing motor (motor unit)
4
defective internally
Swing machinery
5
defective internally
Failure • Large shock is made when the upper struc-
phenomenon ture stops swinging.
Relative • When carrying out the following troubleshooting, set the working mode in the P-mode and turn the
information swing lock switch OFF.
Malfunction of left PPC
1
valve (swing circuit)
Possible causes
and standard
value in normal
state
Malfunction of swing
2
control valve (spool)
Malfunction of swing motor
3
(suction valve)
PC800, 850-8
Cause Standard value in normalcy and references for troubleshooting
aKeep the engine stopped for the preparations, and run it at high idle
during troubleshooting.
Left work equipment control lever
Neutral (After 5 seconds or more)
Operated to swing (in either direc-
The parking brake of the swing motor may malfunction. Check it directly.
aKeep the engine stopped for the preparations, and run it at high idle
during troubleshooting.
Left work equipment control lever
Swing relief (in either direction)
If the oil pressure is still abnormal after adjustment, the safety valve may
malfunction. Check the safety valve directly.
The motor unit of the swing motor may have a defect in it. Check it
directly.
Swing machinery may have a defect in it. Check it directly. (The swing
machinery can be checked by abnormal sound, abnormal heating, metal
dust in the drained oil, etc.)
Cause Standard value in normalcy and references for troubleshooting
aKeep the engine stopped for the preparations, and run it at high idle
during troubleshooting.
Left work equipment control lever
Swing RIGHT/LEFT stroke end
The spool of the swing control valve may malfunction. Check it directly.
The suction valve of the swing motor may malfunction. Check it directly.
(The suction valves of the right and left swing motors can be checked by
exchanging them with each other and seeing the change of the phe-
nomenon.)
(1) Large shock is made when the upper structure stops
swinging in both directions.
Solenoid valve outlet pressure
tion)
(2) Large shock is made when the upper structure stops
swinging in only 1 direction.
Neutral
SEN00794-02
0 MPa {0 kg/cm 2 }
Min. 2.74 MPa
{Min. 28 kg/cm 2 }
Swing relief pressure
+2.5
28.9 MPa
–0.5
+25
2
{295 kg/cm }
–5
PPC valve output pressure
0 MPa {0 kg/cm 2 }
+0.8
2.9 MPa
–0.2
+8
{30 kg/cm }
2
–2
37