Work Equipment Has Big Time Lag; Other Work Equipment Moves When Relieving Single Circuit - Komatsu ecot3 PC300LC-8 Shop Manual

SEN02633-03
H-12 Work equipment has big time lag
Trouble Time lag of work equipment is large.
Related infor-
Set the working mode in P-mode before start.
mation
1 Malfunction of LS-EPC valve
Malfunction of control valve
Possible causes
2 (regeneration valve)
and standard
[boom and arm only]
value in normal
state
Malfunction of control valve
3
(safety-suction valve)
Malfunction of control valve
4 (pressure compensation
valve)
H-13 Other work equipment moves when relieving single circuit
Trouble • When part of work equipment is relieved singly, other parts of work equipment move.
Related infor-
• Set the working mode in P-mode before start.
mation
Possible causes
and standard
Defective seal of control
value in normal
1 valve (pressure compensa-
state
tion valve)
18
Cause Standard value in normal state/Remarks on troubleshooting
a
Regeneration valve of control valve may have malfunction. Check it
directly.
Safety-suction valve of control valve may have malfunction. Check it
directly.
a
Pressure compensation valve of control valve may have malfunc-
tion. Check it directly.
Cause Standard value in normal state/Remarks on troubleshooting
Seal of pressure compensation valve of control valve may be defec-
tive. Check it directly.
Prepare with engine stopped, then run engine at high idle and
carry out troubleshooting.
Travel speed Travel lever
Lo
Hi Lifting operation
The safety-suction valve of the arm or boom may be checked
by replacing it with another one and seeing change of condi-
tion. (However, do not use a safety-suction valve for lowering
the boom or lock valve for this purpose because its set pres-
sure is different.)
40 Troubleshooting
LS-EPC output
pressure
Approx. 1.4 MPa
Neutral
{Approx. 14 kg/cm
0 MPa {0 kg/cm
PC300, 350-8
1
2
}
2
}
1