Greasing the Turntable on a CAT 12G Motor Grader

[MikePhua]

Motor graders, particularly the CAT 12G, are essential machines for various earthmoving tasks, including road construction, leveling, and grading. One of the key components that require proper maintenance is the turntable, which allows the grader’s blade to rotate and adjust to different angles for optimal grading. Regular greasing of the turntable is crucial to ensure smooth operation, prevent wear, and extend the lifespan of the machine. This article will provide a detailed guide on how to grease the turntable of a CAT 12G motor grader, including why this maintenance task is necessary, the tools required, and best practices for the process.
Understanding the Turntable and Its Importance
The turntable on a motor grader, such as the CAT 12G, is the central rotating component that connects the frame of the machine to the articulated section that houses the blade. This part enables the blade to rotate to various angles, allowing the grader to perform tasks like fine grading, leveling, and contouring.
Over time, the turntable experiences a significant amount of wear due to the constant rotation and the stresses of heavy workloads. Without proper lubrication, the turntable bearings and joints can wear down, leading to increased friction, premature failure, and potentially costly repairs. Regular greasing is therefore crucial for keeping the turntable operating smoothly and preventing damage to the machine.
Signs That the Turntable Needs Greasing

• Noise and Squeaking: If you hear squeaking or grinding noises coming from the turntable, it’s a sign that the bearings may be dry and in need of lubrication.
  
• Excessive Wear: Visible signs of wear or rust on the turntable components indicate that lubrication is insufficient, potentially affecting the machine’s overall performance.
  
• Difficulty in Turning: If the grader’s turntable becomes stiff or harder to rotate, it’s a clear indication that the grease has been depleted and needs replenishing.
  

Tools and Materials Required for Greasing
To perform a proper grease job on the CAT 12G’s turntable, the following tools and materials are needed:

• Grease Gun: A high-quality grease gun with the appropriate grease cartridge is essential for applying lubrication to the turntable’s grease fittings.
  
• Grease: Ensure that you are using the right type of grease. For CAT 12G graders, a high-pressure, heavy-duty grease is typically recommended, as it can withstand the high loads and stress placed on the turntable.
  
• Wrenches or Socket Set: Depending on the design, you may need a wrench or socket set to access some parts of the turntable, especially if certain covers or guards need to be removed.
  
• Rags and Cleaning Supplies: Before applying fresh grease, it’s important to clean the grease fittings and surrounding areas to prevent contaminants from entering the system.
  
• Safety Gear: Gloves, safety glasses, and any other personal protective equipment (PPE) should be worn during the process to ensure safety.
  

Step-by-Step Guide to Greasing the Turntable
Greasing the turntable on the CAT 12G involves a series of simple steps that ensure the lubrication is applied correctly. Here is a detailed breakdown:
1. Raise the Grader and Secure It
Ensure that the motor grader is on a flat surface, and engage the parking brake. If necessary, use a hydraulic jack or lift to raise the rear of the machine slightly, ensuring that the turntable is in an accessible position for lubrication. Always ensure the machine is stable before proceeding with maintenance.
2. Locate the Grease Fittings
The grease fittings on the turntable are typically located around the joint where the turntable connects to the rest of the grader. These fittings may be distributed along the circumference of the turntable. Use the machine’s service manual to locate all the grease fittings that require lubrication.
3. Clean the Grease Fittings
Before applying fresh grease, clean the grease fittings with a rag to remove dirt, debris, and old grease. This helps prevent contaminants from entering the lubrication system, which can cause premature wear. Make sure that the fittings are free from any hardened grease build-up.
4. Attach the Grease Gun
Once the fittings are clean, attach the grease gun to each fitting, making sure it’s securely connected. Ensure that the grease gun is filled with the correct type of grease. It’s essential to use the manufacturer-recommended grease to maintain the proper functioning of the bearings and joints.
5. Apply Grease
Slowly pump the grease gun until you see fresh grease coming out of the fitting. This indicates that the internal components are being lubricated. Be sure to apply grease to all fittings, as failure to grease every one can lead to uneven wear and decreased performance. However, do not over-grease, as excessive grease can cause pressure buildup, potentially damaging the seals.
6. Check for Excess Grease
Once the fittings are greased, check for any excess grease that may have leaked out around the turntable joint. Wipe off any excess to keep the area clean and prevent grease from attracting dirt and debris.
7. Test the Turntable
After greasing, slowly rotate the turntable to ensure smooth movement. If you notice any resistance, squeaking, or stiffness, it may indicate that more grease is needed or that the bearings require further inspection.
8. Inspect for Wear and Damage
While greasing, take the opportunity to visually inspect the turntable for any signs of wear or damage. Look for cracks, worn-out components, or any visible issues that may need further attention. Catching problems early can save time and money in repairs.
When to Grease the Turntable
The frequency of greasing will depend on the operating conditions and the frequency of use. In general:

• Under normal conditions, the turntable should be greased every 50-100 hours of operation.
  
• Under harsh conditions, such as extreme temperatures or dusty environments, greasing might be required more frequently.
  

Always consult the machine’s operator manual for the recommended greasing intervals and maintenance schedule.
Common Issues and Solutions
1. Hard to Reach Fittings
Some turntables may have grease fittings that are difficult to access due to the layout of the machine. Using flexible grease gun hoses or extension nozzles can help reach fittings in tight spaces.
2. Over-Greasing
Over-greasing can lead to excess pressure on seals, potentially causing leaks or damage. If excess grease starts to build up around the fittings, reduce the amount you are applying during the next maintenance session.
3. Inconsistent Greasing
Sometimes, not all fittings may be properly greased, leading to uneven wear and potential failure. Always ensure that all grease fittings are lubricated and check for proper grease flow during each maintenance check.
Conclusion
Proper greasing of the turntable on a CAT 12G motor grader is an essential maintenance task that ensures smooth operation, prevents wear, and extends the life of the machine. By following a systematic process and using the correct tools and grease, operators can maintain optimal performance. Regular maintenance not only enhances the efficiency of the grader but also prevents costly repairs caused by neglect. By incorporating these practices into a routine maintenance schedule, operators can keep their CAT 12G motor grader working reliably for years to come.