SANY LATIN AMERICA
7-121
SY195/205/215/225C9 Crawler Hydraulic Excavator
Troubleshooting
Shop Manual - June 2013
H-24 Swing drift excessive
Trouble (1)
●
Hydraulic drift of swing is large (when swing holding brake is ap-
plied).
Related information
●
When swing lock switch is turned ON or when swing holding
brake release switch is in normal position, swing holding brake
operates and upper structure is
fi
xed with disc brake.
Possible causes and standard value
in normal state
Cause
Standard value in normal state/Remarks on troubleshooting
1
Failure of swing hold-
ing brake control lines
Swing holding brake control lines and holding brake pilot valve may be
defective. Check them directly.
2
Malfunction of swing
motor (parking brake)
Parking brake of swing motor may have malfunction. Check it directly.
Trouble (2)
●
Hydraulic drift of swing is large (when swing holding brake is re-
leased).
Related information
●
When swing holding brake release switch is in release position,
swing holding brake is released and upper structure is secured
by only hydraulic pressure.
Possible causes and standard value
in normal state
Cause
Standard value in normal state/Remarks on troubleshooting
1
Malfunction or defec-
tive seal of swing
control valve (spool)
Swing control valve spool may have malfunction or defective seal.
Check it directly.
2
Failure of swing motor
(relief valve)
Seal of relief valve in swing motor may be defective. Check it directly.
3
Failure of swing motor
(makeup valve)
Seal of makeup valve in swing motor may be defective. Check it di-
rectly.
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