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SEN06139-00
H-24 Upper structure overruns remarkably when it stops swinging
Failure
(1) Upper structure overruns excessively when stop swinging in both right and left directions.
Related infor-
q
Perform all troubleshooting with working mode in power mode (P).
mation
Improper adjustment or Mal-
1
function of swing motor
(safety valve)
Probable
causes and cri-
teria
2 Defective swing motor
Failure
(2) Upper structure overruns excessively when stop swinging in only one direction.
Related infor-
q
Perform all troubleshooting with working mode in power mode (P).
mation
Malfunction of swing PPC
1
valve
Probable
Clogged swing PPC slow
2
causes and cri-
return valve
teria
Malfunction of swing control
3
valve (spool)
Malfunction of swing motor
4
(suction valve)
Malfunction of swing motor
5
(check valve)
36
40-500
500 Troubleshooting of hydraulic and mechanical system (H-mode)
H-24 Upper structure overruns remarkably when it stops swinging
Cause
a Be ready with engine stopped, then troubleshoot with engine
high idle.
If normal oil pressure is not obtained by adjustment, swing motor
safety valve may malfunction or may internal defect. Check it.
a Be ready with engine stopped, then troubleshoot with engine
high idle.
Cause
a Be ready with engine stopped, then troubleshoot with engine
high idle.
Left work equipment control
Swing PPC slow return valve may malfunction. Check it.
*
This failure can be checked by interchaning right and left swing
PPC slow return valve and watching how condition changes.
Spool of swing control valve may malfunction. Check the spool.
Suction valve of swing motor may malfunction. Check the valve.
*
This failure can be checked by interchaning right and left suc-
tion valves of swing motor and watching how condition
changes.
Check valve of swing motor may malfunction. Check the valve.
*
This failure can be checked by interchaning right and left suc-
tion valves of swing motor and watching how condition
changes.
Criteria and troubleshooting procedure
Swing lock
Left work equipment
switch
control lever
Swing to hydraulic
ON
Swing lock
Left work equipment
switch
control lever
Swing to hydraulic
ON
Criteria and troubleshooting procedure
lever
Neutral
Left swing
Right swing
Swing relief pressure
28.9 to 3 2.9 MPa
relief
{295 to 335 kg/cm
Leakage from swing
motor
Below 10 l/min
relief
PPC valve output pressure
0 MPa
2
{0 kg/cm
}
2.84 to 3.43 MPa
{29 to 35 kg/cm
PC200, 200LC, 220, 220LC-8M0
2
}
2
}
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