Takeuchi TB 250, Workshop Manual

Page: 323 / 352

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5
ARM
TROUBLESHOOTING
3. Check the spool operation
Disconnect the arm hose connected to the pipe at the
boom foot, then install a pressure gauge in the discon-
nected hose.
• Operate the lever (arm) and measure the pressure.
• If the measured value is within the specifications, the
spool is normal.
Supply pressure: 21.0 MPa
4. Test by replacing the port relief valve
Replace the port relief valve in question with a normal
port relief valve. If the arm cylinder operates with the re-
placement valve, the port relief valve used on the boom
side is faulty.
Make sure to return the port relief valve to its regular
position after the above inspection.
5. Check the arm cylinder
Switch between the arm hose and the bucket hose
connected to the piping at the boom foot.
• Move the lever (bucket) and try to operate the arm
cylinder.
• If the cylinder fails to operate, it is faulty.
Before performing the steps above, fully extend the
bucket cylinder, completely retract the arm cylinder
and lower the bucket to the ground.
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