Fault Cause Analysis:
1 When the excavator bucket moves slowly or lacks power, first check if the output pressure of the PPC valve is normal (normal value: 2.7 MPa).
2 If normal, proceed to check if the bucket spool in the control valve moves smoothly.
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3 If smooth, continue by checking if the pressure compensation valve is functioning correctly or if the pressure compensation plunger moves smoothly.
4 If functioning correctly, check if the leakage rate of the bucket cylinder is within normal limits.
5 If normal, the cause of the slow bucket movement is a malfunction in the bucket safety and inlet valve; repair or replacement is required. Further details:
1 If step 1 is abnormal, the PPC valve is faulty and requires replacement.
2 If step 2 is abnormal, the control valve spool is malfunctioning and requires repair or replacement.
3 If step 3 is abnormal, the pressure compensation valve or plunger is malfunctioning and requires repair or replacement.
4 If step 4 is abnormal, the bucket cylinder piston seal is faulty and requires repair or replacement.
