Travel Speed Is Low - Komatsu PC130-7 Shop Manual

TROUBLESHOOTING
H-18 Travel speed is low
Trouble

• Travel speed is low.

Related
• Carry out the troubleshooting in working mode A.
information
Malfunction of self-reduc-
1
ing pressure valve
Malfunction of travel PPC
2
valve
Possible causes
Malfunction of main relief
3
and standard
valve
value in normal
state
Malfunction of travel control
4
valve (spool)
Malfunction of travel control
5 valve (pressure compensa-
tion valve)
Malfunction of travel control
6
valve (suction valve)
Defective seal of center
7
swivel joint
8 Defective travel motor
9 Defective final drive
20-518
(1)
Cause Standard value in normal state/Remarks on troubleshooting
aPrepare with engine stopped, then run engine at high idling and carry
out troubleshooting.
aPrepare with engine stopped, then run engine at high idling and carry
out troubleshooting.
FORWARD or REVERSE position
Difference between right and left of
aPrepare with engine stopped, then run engine at high idling and carry
out troubleshooting.
Relieved in TRAVEL position
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.
The spool of the travel control valve may have a malfunction. Check it
directly.
The pressure compensation valve of the travel control valve may have a
malfunction. Check it directly.
The suction valve of the travel control valve may have a malfunction.
Check it directly.
The seal of the center swivel joint may be defective. Check it directly.
aPrepare with engine stopped, then run engine at high idling and carry
out troubleshooting.
Relieved in TRAVEL position
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.)
Control levers
All levers in neutral
Travel lever
above
Control levers
Travel lever
Control circuit basic pressure
2.84 – 3.43 MPa
2
{29 – 35 kg/cm }
PPC valve output pressure
2.84 – 3.43 MPa
2
{29 – 35 kg/cm }
Max. 0.4 MPa
2
{Max. 4 kg/cm }
Main relief pressure
36.3 – 39.2 MPa
2
{370 – 400 kg/cm }
Leakage from travel motor
Max. 10 l/min
PC130-7
H-18