Upper Structure Overruns Remarkably When It Stops Swinging - Komatsu PC130-7 Shop Manual

TROUBLESHOOTING
H-24 Upper structure overruns remarkably when it stops swinging
Trouble (1) Upper structure overruns remarkably when it stops swinging in both directions.
Related
• Carry out the troubleshooting in working mode A.
information
Malfunction of swing motor
1
(safety valve)
Possible causes
and standard
value in normal
state
Defective swing motor
2
(motor unit)
Trouble (2) Upper structure overruns remarkably when it stops swinging in only 1 direction.
Related
• Carry out the troubleshooting in working mode A.
information
Malfunction of swing PPC
1
valve
Possible causes
and standard
value in normal
state
Clogging of swing PPC
2
slow return valve
Malfunction of swing con-
3
trol valve (spool)
Defective seal of swing
4
motor (suction valve)
PC130-7
Cause Standard value in normal state/Remarks on troubleshooting
aPrepare with engine stopped, then run engine at high idling and carry
out troubleshooting.
Swing lock switch
LOCK position
aPrepare with engine stopped, then run engine at high idling and carry
out troubleshooting.
Swing lock switch
LOCK position
Cause Standard value in normal state/Remarks on troubleshooting
aPrepare with engine stopped, then run engine at high idling and carry
out troubleshooting.
Right work equipment control lever
The swing PPC slow return valve may be clogged. Check it directly.
The spool of the swing control valve may have a malfunction. Check it
directly.
The seal of the suction valve of the swing motor may be defective.
Check it directly.
Left work equipment
control lever
Relieved in SWING
position
Left work equipment
control lever
Relieved in SWING
position
In NEUTRAL position
In SWING position
H-24
Swing relief pressure
28.9 – 32.9 MPa
{295 – 335 kg/cm
Leakage from swing
motor
Max. 6 l/min
PPC valve output pressure
0 MPa
2
{0 kg/cm }
2.84 – 3.43 MPa
2
{29 – 35 kg/cm }
20-523
2
}
(1)