Troubleshooting
Safety, Operation and Maintenance Manual - Aug 2012
6-37
SY115C9/135C/155H Crawler Hydraulic Excavator
Failure
Causes
Remedy
Unable to swing
In both directions
●
Swing motor (parking brake) failure
●
Bad adjustment or failure of swing motor (safety
valve)
●
Swing motor failure
●
Swing drive failure
●
Check/repair
●
Adjust/replace
●
●
Check/repair
●
Check/repair
In one direction
●
Pilot valve failure
●
Swing control valve (spool) failure
●
Swing motor (feed valve) seal failure
●
Repair/replace
●
Repair/replace
●
Replace
Swing speed slow
Acceleration perfor-
mance bad
●
Swing motor (parking brake) failure
●
Bad adjustment or failure of swing motor (safety
valve)
●
Swing motor failure
●
Brake control line blocked
●
Check/repair
●
Adjust/replace
●
●
Check/repair
●
Remove obstruction
or replace the pipe-
line.
B a d a c c e l e r a t i o n
performance on one
side or swing speed
slow
●
Pilot valve failure
●
Swing motor (pressure compensation valve) fail-
ure
●
Swing motor (feed valve) seal failure
●
Leak on one side the shuttle valve of swing pilot
pressure sensor
●
Repair/replace
●
Repair/replace
●
●
Replace
●
Repair/replace
Too much overrun in swing stoppage
In both directions
●
Bad adjustment or failure of swing motor (safety
valve)
●
Swing motor failure
●
Adjust/replace
●
●
Check/repair
In one direction
●
Pilot valve failure
●
Swing control valve (spool) failure
●
Swing motor (feed valve) seal failure
●
Repair/replace
●
Repair/replace
●
Replace
Too much jerk in swing
stoppage
●
Swing pilot valve failure
●
Swing anti-jerk valve failure
●
Swing relief valve failure
●
Repair/replace
●
Repair/replace
●
Repair/replace
High abnormal noise in
swing stoppage
●
Back pressure valve failure
●
Swing motor (safety valve) failure
●
Swing motor (feed valve) failure
●
Swing system mechanical failure
●
Repair/replace
●
Repair/replace
●
Repair/replace
●
Check/repair