Swing Hydraulic Drift Is Too Big - Komatsu ecot3 PC300LC-8 Shop Manual

SEN02633-03
H-28 Swing hydraulic drift is too big
Trouble (1) • Hydraulic drift of swing is large (when swing holding brake is applied).
Related infor- • When swing emergency reset switch is turned OFF (normal position), swing holding brake operates
mation and upper structure is fixed with disc brake.
Possible causes
Malfunction of swing holding
and standard 1
brake solenoid valve
value in normal
state
Malfunction of swing motor
2
(holding brake)
Trouble (2) • Hydraulic drift of swing is large (when swing holding brake is released).
Related infor- • When swing emergency reset switch is turned ON (in an emergency), swing holding brake is
mation released and upper structure is secured by only hydraulic pressure.
Malfunction of swing control
1
valve (spool)
Malfunction of swing control
2 valve (pressure compensa-
Possible causes
tion valve)
and standard
value in normal
Defective seal of swing
3
state
motor (safety valve)
Defective seal of swing
4
motor (suction valve)
Defective seal of swing
5
motor (check valve)
32
Cause Standard value in normal state/Remarks on troubleshooting
a
Holding brake section of swing motor may have malfunction or inter-
nal defect. Check it directly.
Cause Standard value in normal state/Remarks on troubleshooting
Seal of spool of swing control valve may be defective. Check it
directly.
Seal of pressure compensation valve section of swing control valve
may be defective. Check it directly.
Seal of safety valve of swing motor may be defective. Check it
directly.
Seal of suction valve of swing motor may be defective. Check it
directly.
Seal of check valve of swing motor may be defective. Check it
directly.
Prepare with engine stopped, then run engine at high idle and
carry out troubleshooting.
Swing lever
Neutral
Left or Right
40 Troubleshooting
Solenoid valve output pressure
2
0 MPa {0 kg/cm }
2.84 – 3.43 MPa
2
{29 – 35 kg/cm }
PC300, 350-8
1