Swing Acceleration Or Swing Speed Is Low - Komatsu PC130-7 Shop Manual

TROUBLESHOOTING
H-23 Swing acceleration or swing speed is low
Trouble (1) Swing acceleration or swing speed is low in both directions.
Related
• Carry out the troubleshooting in working mode A.
information
Malfunction of swing con-
1 trol valve (pressure com-
pensation valve)
Malfunction of swing bleed
2
valve
Malfunction of swing motor
3
(parking brake)
Possible causes
Malfunction of swing motor
and standard 4
(safety valve)
value in normal
state
Defective swing motor
5
(motor unit)
6 Defective swing machinery
Trouble (2) Swing acceleration or swing speed is low in only 1 direction.
Related
• Carry out the troubleshooting in working mode A.
information
Malfunction of swing PPC
1
valve
Possible causes
and standard
value in normal
state
Clogging of swing PPC
2
slow return valve
Malfunction of swing con-
3
trol valve (spool)
Defective seal of swing
4
motor (suction valve)
20-522
(1)
Cause Standard value in normal state/Remarks on troubleshooting
The pressure compensation valve of the swing control valve may have a
malfunction. Check it directly.
The swing bleed valve of the control valve may have a malfunction.
Check it directly.
The parking brake of the swing motor may have a malfunction. Check it
directly.
aPrepare with engine stopped, then run engine at high idling and carry
out troubleshooting.
Swing lock switch
LOCK position
aPrepare with engine stopped, then run engine at high idling and carry
out troubleshooting.
Swing lock switch
LOCK position
The swing machinery may have a defect in it. Check it directly. (It may
be checked by abnormal sound, abnormal heating, metal chips in drain
oil, etc.)
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 swing PPC slow return valve may be clogged. Check it directly.
The spool of the swing control valve may have a malfunction. Check it
directly (including the stroke limiting mechanism).
The seal of the suction valve of the swing motor may be defective.
Check it directly.
Left work equipment
control lever
Relieved in SWING
position
Left work equipment
control lever
Relieved in SWING
position
In NEUTRAL position
In SWING position
H-23
Swing relief pressure
28.9 – 32.9 MPa
{295 – 335 kg/cm
Leakage from swing
motor
Max. 6 l/min
PPC valve output pressure
0 MPa
2
{0 kg/cm }
2.84 – 3.43 MPa
2
{29 – 35 kg/cm }
PC130-7
2
}