Addressing Hydraulic Slack in JLG Boom Lifts

[MikePhua]

JLG boom lifts are essential machines for aerial work, offering versatility and ease of access at great heights. However, like all heavy machinery, they can experience mechanical issues that hinder their performance. One such issue is hydraulic slack, which affects the lift's ability to operate efficiently and safely. This article delves into what hydraulic slack is, why it occurs, and how to resolve it for optimal boom lift operation.
Understanding Hydraulic Slack in JLG Boom Lifts
Hydraulic slack, sometimes referred to as "lag" or "delay," occurs when there is a noticeable delay or looseness in the hydraulic system when the boom is being raised, lowered, or extended. It often results in the boom's movement feeling jerky, unresponsive, or imprecise. This problem can lead to inefficient performance, and if left unchecked, may pose a safety risk for operators working at heights.
Causes of Hydraulic Slack
There are several potential causes of hydraulic slack in a JLG boom lift:

1. Air in the Hydraulic System:
   Air trapped in the hydraulic lines can cause a delay in the hydraulic fluid's pressure buildup, leading to slack or sluggish movement. This can happen if the hydraulic system has recently been serviced or if there’s a leak allowing air to enter.
   
2. Worn or Faulty Hydraulic Seals:
   Over time, seals within the hydraulic system can wear out, causing fluid leaks or allowing air to infiltrate the system. This can significantly impact the efficiency of the hydraulics, resulting in slack during boom movements.
   
3. Low Hydraulic Fluid Levels:
   Insufficient hydraulic fluid can prevent the system from building adequate pressure, causing the boom to lag or move sluggishly. It’s important to regularly check fluid levels and top them off as needed.
   
4. Hydraulic Pump Issues:
   A failing or underperforming hydraulic pump can struggle to supply the necessary pressure to the hydraulic system, resulting in slack. If the pump is worn or malfunctioning, it may need to be replaced to restore normal operation.
   
5. Clogged Hydraulic Filters:
   Hydraulic filters serve to remove contaminants from the fluid, ensuring smooth operation of the system. Over time, filters can become clogged, which restricts the flow of fluid and impacts the hydraulic system’s performance, contributing to slack.
   

How to Fix Hydraulic Slack
Addressing hydraulic slack in a JLG boom lift requires a systematic approach to identify and resolve the root cause. Here are the steps to take:

1. Check for Air in the Hydraulic System:
   If air is suspected in the system, bleeding the hydraulics can help eliminate it. The machine’s manual typically provides instructions on how to perform this procedure. After bleeding the system, check the boom for smooth, responsive movement.
   
2. Inspect Hydraulic Seals:
   Inspect the hydraulic seals for wear or damage. If any seals are found to be leaking or deteriorating, they should be replaced to ensure a tight seal. Seals play a critical role in maintaining the system’s pressure and preventing air from entering.
   
3. Top Up Hydraulic Fluid:
   Low hydraulic fluid levels are a common cause of slack. Check the fluid levels regularly, and ensure that they are within the recommended range. Use the correct type of hydraulic fluid as specified in the operator’s manual, and add more if necessary. Be cautious of overfilling, as this can also lead to other issues in the system.
   
4. Examine the Hydraulic Pump:
   A worn or faulty hydraulic pump may need to be replaced to restore proper pressure. If the pump is functioning below its optimal capacity, it might not generate enough pressure to operate the boom lift properly, resulting in slack.
   
5. Replace or Clean Hydraulic Filters:
   Clogged filters can hinder the flow of hydraulic fluid. Inspect the hydraulic filters and clean or replace them if necessary. A clean filter ensures that the system receives the proper flow of fluid, preventing slack and other performance issues.
   

Testing and Verifying the Fix
After addressing the potential causes of hydraulic slack, it is crucial to test the boom lift to ensure that the issue has been resolved. Operate the boom lift and observe its performance—check for smooth and responsive movement in all directions. If slack persists, additional diagnostics may be required to pinpoint any underlying issues.
Preventing Future Hydraulic Slack
Preventative maintenance is key to ensuring that hydraulic slack does not become a recurring issue. Regularly check and maintain the hydraulic fluid levels, replace worn seals, and keep the hydraulic system clean and free from contaminants. Timely servicing of the hydraulic pump and filters will also help ensure the longevity and efficiency of the machine.
Conclusion
Hydraulic slack in a JLG boom lift can significantly affect its performance, but by understanding the causes and following proper troubleshooting procedures, operators can quickly address the issue. Regular maintenance and inspections are essential in preventing hydraulic slack and keeping the machine running smoothly, ensuring both safety and productivity on the job site.