Resealing a Leaking Manlift Hub

[MikePhua]

Manlifts are essential equipment used across various industries such as construction, maintenance, and warehousing. They provide vertical mobility and are indispensable in accessing hard-to-reach areas. However, like any heavy machinery, manlifts are prone to mechanical issues over time. One common problem faced by owners and operators of manlifts is a leaking hub, which can significantly impact the machine’s performance and safety. In this article, we will discuss the causes of hub leaks, how to reseal a leaking hub, and preventive measures to keep your manlift in top condition.
Understanding the Importance of the Hub in a Manlift
Before delving into the issue of leaking hubs, it is important to understand the role of the hub in a manlift. The hub is an essential part of the drive system, responsible for connecting the wheel or track to the axle. In manlifts, hubs allow for smooth and controlled movement, and they house various bearings and seals that prevent fluid leakage.
Hubs are subjected to considerable pressure, especially when the equipment is lifted or moved with a heavy load. Over time, seals can degrade, leading to oil or hydraulic fluid leaks, which can cause serious damage if not addressed promptly.
Common Causes of Hub Leaks
Hub leaks are a relatively common issue in manlifts, and understanding their root causes can help in diagnosing and fixing the problem efficiently.
1. Worn Out Seals
The most common cause of a leaking hub is the deterioration of the seals. These rubber or synthetic seals prevent the escape of lubricants and oils from the hub. Over time, seals can wear out due to heat, friction, and constant pressure, resulting in leaks.
2. Contamination
Contaminants such as dirt, dust, and debris can enter the hub, damaging seals and causing leaks. Contaminated oil or hydraulic fluid can also accelerate wear on the seals, making them more prone to leaking.
3. Improper Installation or Alignment
If the hub is not installed correctly or if the axle and hub are not properly aligned, excessive stress can be placed on the seals. This can lead to premature failure and leakage. This issue is often seen in poorly maintained equipment or during improper repairs.
4. Overfilling of Fluids
Excessive fluid inside the hub can cause it to leak. If the manufacturer’s recommended fluid level is exceeded, pressure builds up inside the hub, which can force seals to break or wear out quickly.
5. Bearing Failures
In some cases, bearing failures can result in the hub becoming misaligned, which in turn causes leakage. Bearings within the hub are under constant stress, and a failure can lead to misalignment, increasing the likelihood of fluid leakage.
Steps to Reseal a Leaking Hub
If you notice oil or hydraulic fluid leaking from the hub, it is crucial to address the issue immediately to prevent further damage and maintain the safety and functionality of your manlift. Below is a step-by-step guide on how to reseal a leaking hub.
1. Gather Tools and Materials
Before starting the resealing process, gather all the necessary tools and materials, which may include:

• Wrenches and socket sets
  
• Hydraulic jack and jack stands
  
• Cleaning agents (degreasers, brake cleaner)
  
• Replacement seals and O-rings
  
• New oil or hydraulic fluid
  
• Torque wrench
  
• Safety gloves and goggles
  

2. Secure the Equipment
Ensure that the manlift is safely parked on a level surface and that the equipment is fully powered off. Use a hydraulic jack to lift the manlift, if necessary, and secure it with jack stands for safety. Make sure the area around the hub is clear of debris to avoid contamination.
3. Drain the Fluids
Before opening the hub, you will need to drain the oil or hydraulic fluid. This prevents further spillage during disassembly and allows for a clean environment when working on the hub. Use an appropriate container to catch the drained fluid.
4. Disassemble the Hub
Using the proper tools, remove the wheel or track, as well as any surrounding components that may be in the way. Depending on the design of the manlift, you may need to remove bolts or pins securing the hub to the axle or other parts. Carefully disassemble the hub, taking note of the order of components for reassembly.
5. Inspect the Hub and Components
Before resealing, inspect the hub and its components for any signs of wear or damage. Check the bearings for smoothness and replace them if necessary. Examine the hub for cracks or other damage that could affect its performance. Ensure that the seal groove is clean and free of debris.
6. Clean the Hub
Clean the hub thoroughly to remove any old fluid, dirt, or contaminants. Use a degreaser or brake cleaner and a clean rag to wipe down all surfaces, including the seal area. This ensures that no debris or dirt is trapped when you apply the new seal, which can prevent a proper seal.
7. Replace the Seals
Install the new seals and O-rings carefully, making sure they fit snugly into their designated grooves. It is essential to use the exact seal replacements recommended by the manufacturer to ensure a proper fit and long-lasting results. Improper seals can lead to leakage and damage to the hub.
8. Reassemble the Hub
Once the seals are in place, carefully reassemble the hub. Replace any components that were removed and ensure that everything is aligned correctly. Use a torque wrench to tighten all bolts and fasteners to the manufacturer’s recommended specifications to prevent future issues.
9. Refill the Fluid
Once the hub is resealed and reassembled, refill it with the recommended oil or hydraulic fluid. Be careful not to overfill the hub, as excessive pressure can lead to future leaks. Follow the manufacturer’s guidelines for proper fluid levels.
10. Test the Manlift
Lower the manlift and test it for functionality. Check for any signs of leakage around the hub. If there are no signs of leaks and the manlift is operating smoothly, the resealing job is complete. If the issue persists, further inspection may be needed.
Preventive Measures and Maintenance Tips
While resealing a leaking hub can be a straightforward task, preventive measures can go a long way in avoiding future leaks and costly repairs.

• Regular Inspections: Periodically inspect the hubs and seals for any signs of wear or leakage. Early detection can prevent larger issues down the line.
  
• Clean the Equipment: Keep the manlift clean, especially around the hub and seal area, to prevent dirt and debris from causing damage.
  
• Use Quality Fluids: Always use the recommended type of oil or hydraulic fluid to prevent contamination or pressure buildup inside the hub.
  
• Proper Maintenance: Follow the manufacturer’s maintenance schedule for oil changes, lubrication, and other servicing tasks to keep the manlift in good condition.
  

Conclusion
A leaking hub can lead to significant downtime and potential damage to a manlift, making it crucial to address such issues promptly. By understanding the causes of hub leaks, following the steps for resealing, and implementing preventive measures, operators can extend the lifespan of their equipment and ensure smooth operations. Regular maintenance, including the inspection and replacement of seals, is essential for preventing hub leaks and keeping the manlift in top working condition.