Sinoboom Hydraulic Cylinder Rebuild Guide
This guide covers the rebuild process for lift cylinders on Sinoboom SE and ME series scissor lifts. A proper rebuild can restore cylinder performance at a fraction of replacement cost.
When to Rebuild
Signs your cylinder needs attention:
- Visible oil leaking past rod seal
- Slow or jerky lift operation
- Cylinder drift when holding position
- Scoring visible on rod surface
Required Materials
- Seal kit specific to your cylinder model
- Clean hydraulic fluid
- Lint-free rags
- Seal pick set
- Cylinder hone (if needed)
Safety Precautions
Before starting:
- Lower platform completely
- Release hydraulic pressure
- Support platform with safety props
- Disconnect battery
Removal Process
Step 1: Access the Cylinder
- Remove any covers or guards
- Identify and mark hydraulic line connections
- Have drain pan ready
Step 2: Disconnect Hydraulics
- Cap all open fittings immediately
- Note fitting sizes and types
- Inspect fittings for damage
Step 3: Remove Cylinder
- Support cylinder weight
- Remove mounting hardware
- Extract carefully to avoid damage
Disassembly
Opening the Cylinder
- Clean exterior thoroughly
- Secure cylinder in soft-jaw vise
- Remove gland nut or snap ring
- Extract rod assembly
Inspecting Components
Check for:
- Rod surface scoring or pitting
- Bore surface condition
- Piston wear
- Gland damage
Seal Installation
Preparing Seals
- Inspect all new seals for damage
- Lightly oil seals before installation
- Use proper seal installation tools
Installing Rod Seals
- Start seal squarely
- Work around circumference evenly
- Avoid scratching seal lip
Installing Piston Seals
- Follow manufacturer sequence
- Note orientation marks
- Verify proper seating
Reassembly
Reinserting Rod Assembly
- Lubricate bore generously
- Guide rod in straight
- Avoid cocking piston
Torquing Gland
- Use specified torque value
- Apply thread sealant if required
- Verify alignment
Reinstallation
Mounting Cylinder
- Verify mounting surfaces are clean
- Install new mounting hardware
- Torque to specification
Reconnecting Hydraulics
- Use new O-rings on fittings
- Tighten in proper sequence
- Check for leaks
Testing
After installation:
- Cycle cylinder slowly several times
- Check for external leaks
- Verify smooth operation
- Test under load
- Re-check fittings after warm-up
