Project Overview: Slewing Ring Bearing Replacement for Liebherr Crane at Chu Lai Port

Project: Slewing Ring Bearing Replacement for Liebherr Harbor Crane
Client / Investor: CHU LAI PORT
Location: Chu Lai Port Quayside, Quang Nam Province
Execution Timeline: Q4/2025
Key Supporting Equipment: 5-ton forklift, 220-ton all-terrain mobile crane (for structural heavy lifting), active Liebherr harbor crane (target equipment for repair).
Project Objective: Swiftly restore the harbor crane to its original operating capacity, ensuring continuous port operational readiness for the client.

SCOPE OF WORK: SLEWING RING BEARING REPLACEMENT FOR LIEBHERR CRANE AT CHU LAI PORT

Inspect the current structural and mechanical condition of the Liebherr crane, specifically the worn slewing ring bearing, raceways, and adjacent structures.
Collect detailed crane data, serial numbers, and slewing bearing technical specifications based on Liebherr OEM documentation.
Identify potential operational hazards and workplace safety risks.

Formulate step-by-step disassembly and reassembly procedures tailored specifically to the Liebherr crane on-site.
Establish lifting sequences, positioning of the 220-ton auxiliary mobile crane, 5-ton forklift, and supporting lifting gear.
Plan resource allocation, specialized tooling, materials, and workforce.
Formulate comprehensive HSE, fire prevention, and environmental protection plans throughout execution.

3. Mobilization of Materials and Equipment:

Inspect and verify that the replacement slewing ring bearing is supplied in full compliance with OEM specifications and quality standards (with authentic CO/CQ certificates).
Prepare all OEM-specified consumables (high-tensile bolts, nuts, washers, specialized lubricants, degreasing chemicals) per Liebherr standards.
Mobilize the 220-ton mobile crane, 5-ton forklift, certified modular scaffolding, and specialized tooling (hydraulic torque wrenches, bolt tensioners, laser alignment instruments, flatness gauges).
Provide complete PPE gear for all engineering personnel.

4. Site Preparation and Safety Zoning:

Barricade and establish a dedicated safety perimeter around the work zone.
Clear obstacles to provide ample working radius for auxiliary crane operations and component staging.
Verify jetty/pavement load-bearing capacity at outrigger positions and component staging areas.

Rig and hoist the crane superstructure (including engine housing, winches, gearboxes, machinery house) clear of the undercarriage/pedestal.
Lower and secure the superstructure safely onto designated heavy-duty temporary support stands.

De-torque and remove all high-tensile bolts securing the slewing bearing to the superstructure and undercarriage flange. Mark and record positions for precise reassembly.
Inspect bolt condition and segregate items requiring replacement.
Rig and hoist the old slewing bearing using certified lifting accessories and transfer to the staging area.

Thoroughly clean mounting mating surfaces on both the superstructure and undercarriage flanges. Remove rust, grease, debris, and old coatings.
Verify flange flatness, parallelism, and surface integrity using precision instruments (straight edges, dial gauges, flatness feelers). Ensure zero warping or surface defects.
Perform flange surface repairs/lapping if necessary in accordance with OEM tolerances.

Perform visual inspection of the new slewing ring bearing for transit damage.
Verify all technical dimensions, gear teeth profiles, and mounting hole alignments against OEM drawings.

Rig and lower the new slewing bearing into position, aligning accurately per Liebherr technical guidelines.
Install high-tensile mounting bolts following the specified cross-pattern sequence, torque limits, and multi-stage tensioning procedures stipulated in Liebherr engineering manuals.
Use calibrated hydraulic torque wrenches to guarantee exact torque values.

Hoist the crane superstructure and mate it back onto the undercarriage flange with millimeter precision.
Fasten superstructure-to-bearing bolts following calibrated torque specifications and tightening sequences. Reinstall the main boom, operator cabin, and disconnected piping, cabling, and instrumentation.

Reconnect all hydraulic lines, electrical power wiring, and control bus cabling.
Inspect and charge specialized grease/lubricants into the new slewing bearing raceways and gear teeth per Liebherr lubrication charts.

Re-energize electrical and hydraulic systems.
Test electrical, hydraulic, and safety interlocks post-connection.
Perform low-speed no-load slewing trials, verifying smooth rotation, zero abnormal noise, no binding, and minimal vibration.
Inspect hydraulic connections for fluid leaks.

Conduct static and dynamic load testing at rated capacity.
Monitor slewing bearing behavior under load (deflection, raceway noise, operating temperature).
Verify all crane safety devices and load moment limiters during testing.

2. Fine-Tuning and Re-Torquing:

Re-check and confirm torque values on all slewing ring bolts after initial operating cycles.
Fine-tune operational parameters to ensure peak lifting performance and safety.

Hand over the fully repaired and load-certified harbor crane to Chu Lai Port authorities.
Provide complete as-built documentation, material test certificates (CO/CQ), load test reports, and operating/maintenance manuals for the new slewing ring bearing,
Advise on periodic preventive maintenance and greasing schedules to ensure long-term equipment reliability.

Clean up work areas and restore quayside conditions.
Collect and dispose of waste materials in strict compliance with environmental regulations.
Demobilize all auxiliary cranes, specialized tools, and engineering personnel from the site.