Hydraulic Drift Of Swing Is Large - Komatsu PC130-7 Shop Manual

TROUBLESHOOTING
H-27 Hydraulic drift of swing is large
Trouble (1) When swing holding brake is applied
• When the swing lock switch is in the LOCK position or when the swing holding brake release switch is
Related in the normal position, the swing holding brake operates and the upper structure is fixed with the disc
information brake.
• Carry out the troubleshooting in working mode A.
Possible causes Malfunction of swing hold-
1
and standard ing brake solenoid valve
value in normal
state
Malfunction or internal
2 defect of swing motor
(parking brake)
Trouble (2) When swing holding brake is released
• When the swing holding brake release switch is in the RELEASE position, the swing brake is released
Related
and the upper structure is secured by only hydraulic pressure.
information
• Carry out the troubleshooting in working mode A.
Defective seal of swing
1
control valve (spool)
Defective seal of swing
Possible causes 2
control valve (safety valve)
and standard
Defective seal of swing
value in normal
3 control valve (suction
state
valve)
Defective seal of swing
4 control valve (shockless
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.
Right work equipment control lever
The parking brake of the swing motor may have a malfunction or a
defect in it. Check it directly.
Cause Standard value in normal state/Remarks on troubleshooting
The seal of the spool of the swing control valve may be defective.
Check it directly.
The seal of the safety valve of the swing control valve may be defective.
Check it directly.
The seal of the suction valve of the swing control valve may be defec-
tive. Check it directly.
The seal of the shockless valve of the swing control valve may be defec-
tive. Check it directly.
In NEUTRAL position
In SWING position
Solenoid valve output pressure
0 MPa
2
{0 kg/cm }
2.84 – 3.43 MPa
2
{29 – 35 kg/cm }
20-525
H-27
(1)