I. Basic Model Compatibility

II. Seal Components Included in Kit

III. Seal Material Standards

IV. Classification of Supply Versions

1. Genuine Vo lvo OEM Kit

   
   

   Standard factory dimensions with zero tolerance deviation, 12-month warranty, ideal for heavy-duty mining applications.
2. Brand New OEM Aftermarket Repair Kit

   
   

   Replicated dimensions with imported rubber compound, fully interchangeable, 3–6 month warranty, regular replacement for construction sites.
3. Economy Aftermarket Kit

   
   

   Standard NBR rubber, low cost, suitable for short-term emergency repairs.

V. Applicable Fault Conditions for Replacement

• Oil seepage or dripping on the outer surface of boom cylinder piston rod
• Internal cylinder leakage: Automatic boom drop and weak lifting performance
• Insufficient cylinder pressure and slow boom lifting movement
• Damaged wiper seal causing sediment intrusion and piston rod scoring

VI. Disassembly & Assembly Instructions

• Release residual pressure of hydraulic system and fully retract the boom cylinder before disassembly
• Remove burrs and scratches on cylinder barrel and piston rod surface; polish minor scoring marks
• Apply factory grease on seals during installation; do not pry seals hard to prevent lip damage
• Install piston seals and guide bands evenly without twisting or cutting
• Extend and retract the boom without load for 5–10 cycles to vent air after assembly; confirm zero leakage before operation

VII. Key Operating Parameters of Matching EC380 Excavator