How to replace the slewing bearing

Replacing a slewing bearing is a complex and precise task that requires careful planning, proper tools, and adherence to safety protocols. Here’s a step-by-step guide on how to replace a slewing bearing.

Slewing bearing replacement

1. Preparation

Gather Tools and Equipment:

Lifting equipment (e.g., crane or hoist)

Torque wrenches

Hydraulic jacks (if necessary)

Alignment tools (e.g., dial indicators)

Cleaning supplies (e.g., solvents, rags)

Replacement bolts, washers, and nuts

New slewing bearing

Lubrication (grease)

Protective gear (e.g., gloves, safety glasses)

Safety Precautions:

Ensure the work area is clear of unnecessary personnel.

Lockout and tagout the equipment to prevent accidental operation.

Wear appropriate personal protective equipment (PPE).

Prepare the New Bearing:

Inspect the new slewing bearing for any damage during transit.

Check the manufacturer's specifications and ensure the replacement bearing matches the existing one in size, load capacity, and mounting configuration.

Document the Existing Setup:

Take notes or photos of the current bearing installation, including the orientation, bolt patterns, and any shims or spacers used. This will help during the reinstallation process.

2. Remove the Old Bearing

Disconnect and Remove Components:

Disconnect any components attached to the slewing bearing, such as motors, gears, or hydraulic lines.

Mark the positions of any components for reassembly.

Support the Structure:

Use appropriate lifting equipment to support the structure connected to the slewing bearing (e.g., the upper structure of a crane or the platform of a machine).

Ensure that the load is stable and securely supported.

Loosen and Remove Bolts:

Loosen the mounting bolts that secure the slewing bearing to the structure. Use a torque wrench or impact wrench as needed.

Gradually and evenly remove the bolts, working in a star pattern to avoid distorting the bearing or the mounting surfaces.

Collect and discard the old bolts, nuts, and washers, as they should be replaced with new ones.

Separate the Bearing:

Carefully separate the slewing bearing from the structure. Depending on the size and weight of the bearing, you may need to use hydraulic jacks or other lifting equipment to lift the bearing away from the mounting surface.

Ensure the old bearing is lifted evenly to avoid binding or damaging the surrounding components.

Clean the Mounting Surface:

Clean the mounting surfaces thoroughly to remove any old grease, dirt, or debris.

Inspect the mounting surfaces for any damage, wear, or corrosion. Repair or replace any damaged areas before installing the new bearing.

3. Install the New Bearing

Position the New Bearing:

Align the new slewing bearing with the mounting holes on the structure.

Lower the bearing into place carefully, ensuring that it sits evenly on the mounting surface.

If necessary, use alignment tools like dial indicators to ensure the bearing is correctly positioned.

Install New Bolts:

Insert the new bolts, washers, and nuts into the mounting holes. Start by hand-tightening the bolts to secure the bearing in place.

Gradually tighten the bolts in a star pattern to ensure even pressure distribution across the bearing.

Use a torque wrench to tighten the bolts to the manufacturer's specified torque settings. Over-tightening or under-tightening can lead to bearing failure.

Check and Adjust Bearing Alignment:

Use alignment tools to check the bearing’s position. Ensure it is level and properly aligned with the mating surfaces.

Make any necessary adjustments before fully securing the bearing.

Lubricate the Bearing:

Apply the recommended grease to the bearing according to the manufacturer’s specifications.

Rotate the bearing slowly to distribute the grease evenly around the raceway.

4. Reassemble and Test

Reconnect Components:

Reattach any components that were disconnected during the removal process, such as motors, gears, or hydraulic lines.

Ensure all connections are secure and properly aligned.

Perform a Function Test:

Slowly operate the equipment to ensure the new bearing is functioning correctly.

Listen for any unusual noises and monitor the bearing’s performance during initial operation.

Check for any leaks, loose connections, or signs of misalignment.

Final Inspection:

After the initial operation, inspect the bearing and surrounding components for any issues.

Re-tighten the bolts if necessary and ensure the bearing is operating smoothly.

Document the Installation:

Record the details of the installation, including torque values, alignment measurements, and any observations during the function test.

Schedule follow-up inspections as part of routine maintenance.

By following these steps carefully, you can ensure the slewing bearing is replaced correctly and will perform reliably in its application.