Komatsu PC130-7, Shop Manual

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20-518
PC130-7
TROUBLESHOOTING
H-18 Travel speed is low
Trouble • Travel speed is low.
Related
information
• Carry out the troubleshooting in working mode A.
Possible causes
and standard
value in normal
state
Cause Standard value in normal state/Remarks on troubleshooting
1
Malfunction of self-reduc-
ing pressure valve
a
Prepare with engine stopped, then run engine at high idling and carry
out troubleshooting.
Control levers Control circuit basic pressure
All levers in neutral
2.84 – 3.43 MPa
{29 – 35 kg/cm
2
}
2
Malfunction of travel PPC
valve
a
Prepare with engine stopped, then run engine at high idling and carry
out troubleshooting.
Travel lever PPC valve output pressure
FORWARD or REVERSE position
2.84 – 3.43 MPa
{29 – 35 kg/cm
2
}
Difference between right and left of
above
Max. 0.4 MPa
{Max. 4 kg/cm
2
}
3
Malfunction of main relief
valve
a
Prepare with engine stopped, then run engine at high idling and carry
out troubleshooting.
Control levers Main relief pressure
Relieved in TRAVEL position
36.3 – 39.2 MPa
{370 – 400 kg/cm
2
}
If the oil pressure does not become normal after adjustment, the main
relief valve may have a malfunction or a defect in it. Check the main
relief valve directly.
4
Malfunction of travel control
valve (spool) The spool of the travel control valve may have a malfunction. Check it
directly.
5
Malfunction of travel control
valve (pressure compensa-
tion valve)
The pressure compensation valve of the travel control valve may have a
malfunction. Check it directly.
6
Malfunction of travel control
valve (suction valve) The suction valve of the travel control valve may have a malfunction.
Check it directly.
7
Defective seal of center
swivel joint
The seal of the center swivel joint may be defective. Check it directly.
8 Defective travel motor
a
Prepare with engine stopped, then run engine at high idling and carry
out troubleshooting.
Travel lever Leakage from travel motor
Relieved in TRAVEL position Max. 10
l
/min
9 Defective final drive
The final drive may have a defect in it. Check it directly. (It may be
checked by abnormal sound, abnormal heating, metal chips in drain oil,
etc.)
H-18
(1)