5-8
5
TRAVELING
TROUBLESHOOTING
TRAVELING
Right or left travel is impossible
1
Check the operation of
actuators other than of
the travel motor
Normal
2
Check
the pilot valve
(Travel)
Faulty
Repair
or replace the pilot
valve (travel)
Normal
3
Check
the spool opera-
tion
Faulty
Repair
or replace the housing
block
Normal
4 Check the swivel joint
Faulty
Repair
or replace the swivel
joint
Normal
5
Check
the counter bal-
ance valve
Faulty
Repair
or replace the counter
balance valve
Normal
6 Check the travel motor
Faulty
Repair
or replace the travel
motor
1. Check the operation of actuators other than of the
travel motor.
If the right or left travel is impossible, operate each ac-
tuator
of the devices listed in the table on the right.
If operation is faulty, inspect the main relief valve and
piston pump.
2. Check the pilot valve (travel)
Disconnect the hose connecting the pilot valve and the
control valve (travel block) from the control valve. Fit a
pressure gauge to the hose just disconnected.
• Insert a plug into the control valve port.
• Operate the lever (travel) and measure the pres-
sur
e.
• If the pressure is between 0 and 3.4 MPa depending
on the lever angle, the pilot valve is normal.
Problem
Lever to
operate
Device to check
Relief valve Pump
Right
travel
Boom
TB228, 235: R2 TB228, 235: P2
TB250: R1 TB250: P1
Left travel Arm
TB228, 235: R1 TB228, 235: P1
TB250: R2 TB250: P2
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