Komatsu ecot3 PC300LC-8 Shop Manual page 835

40 Troubleshooting
Trouble (2) • Swing acceleration or swing speed is low in only one direction.
Related infor-
• Set the working mode in P-mode before start.
mation
Malfunction of swing PPC
1
valve
Malfunction of swing control
2
valve (spool)
Possible causes
Malfunction of swing control
and standard
3 valve (pressure compensa-
value in normal
tion valve)
state
Defective seal of swing
4
motor (suction valve)
Defective seal of swing
5
motor (check valve)
PC300, 350-8
Cause Standard value in normal state/Remarks on troubleshooting
a
Spool of swing control valve may have malfunction. Check it directly.
Pressure compensation valve of swing control valve may have mal-
function. Check it directly.
Seal of suction valve of swing motor may be defective. Check it
directly.
a
Seal of check valve of swing motor may be defective. Check it
directly.
a
Prepare with engine stopped, then run engine at high idle and
carry out troubleshooting.
Swing lever
Neutral
Left or Right
Suction valves on right side and left side may be checked by
replacing them with each other and seeing change of condi-
tion.
Check valves on right side and left side may be checked by
replacing them with each other and seeing change of condi-
tion.
SEN02633-03
PPC valve output pressure
2
0 MPa {0 kg/cm }
Min. 2.7 MPa
2
{Min. 28 kg/cm }
29