How to Take Up Slack in the Pivot Bushing of a Hough 65

[MikePhua]

Understanding Pivot Bushing Slack
Pivot bushings are critical components in heavy machinery such as the Hough 65 loader. They act as the bearing surfaces allowing movement between pivoting parts like arms and frames. Over time, these bushings can develop slack—excessive play or looseness—due to wear, which affects machine stability, precision, and overall performance. Taking up slack means adjusting or repairing the pivot bushings to restore tightness and reduce unwanted movement.
Key Terminology

• Pivot Bushing: A cylindrical lining fitted in a pivot point to reduce friction and wear between moving parts.
  
• Slack: Unwanted looseness or play in mechanical joints that compromises stability.
  
• Wear: Material loss from surfaces due to friction or impact.
  
• Pin and Bushing Assembly: A setup where a pin rotates or moves inside a bushing, creating the pivot point.
  
• Reaming: Machining process to slightly enlarge holes to restore roundness or fit.
  
• Sleeving: Installing a replacement lining inside a worn bushing or housing.
  

Causes of Slack in Pivot Bushings

• Normal operational wear caused by repetitive motion.
  
• Lack of lubrication leading to accelerated abrasion.
  
• Contaminants like dirt or grit entering the joint.
  
• Heavy loading and impacts causing deformation.
  
• Corrosion or rust weakening the bushing material.
  

Diagnosis of Slack in the Hough 65 Pivot

• Visually inspect for signs of movement beyond normal tolerance.
  
• Test by manually moving the connected components to detect looseness.
  
• Measure clearance between the pin and bushing.
  
• Listen for unusual noises such as knocking or rattling during operation.
  
• Check lubrication condition and any evidence of contamination.
  

Methods to Take Up Slack

• Adjusting Pivot Pins: Some machines allow tightening of pivot pins or bolts that hold the bushings. Check for adjustment points.
  
• Replacing Worn Bushings: The most definitive fix involves removing worn bushings and installing new ones.
  
• Sleeving the Bushing Housing: If the housing is worn, it may need sleeving to restore proper dimensions before new bushings are installed.
  
• Reaming and Oversizing: Machining the bushing bore to a slightly larger size to accept an oversized bushing or sleeve.
  
• Using Shims or Washers: In some cases, shims can be added to reduce play if minor adjustments are possible.
  
• Lubrication Maintenance: Ensuring proper and regular greasing to minimize future wear.
  

Tools and Equipment Needed

• Hydraulic press or bushing driver for removing/installing bushings.
  
• Reamer or boring machine for precision machining.
  
• Calipers and micrometers for measuring clearances.
  
• Torque wrench for proper tightening of fasteners.
  
• Grease guns and quality lubricants.
  

Real-World Example and Insights
A Hough 65 owner reported excessive play in the loader arm pivot causing poor control and a rattling noise. The bushings were inspected and found worn beyond acceptable limits. The solution involved removing the pivot pin, pressing out the old bushings, machining the pivot housing to clean and size it accurately, then installing new bushings with proper grease channels. After reassembly and adjustment, the slack was eliminated and operational stability restored.
Maintenance Tips to Prevent Future Slack

• Maintain a regular lubrication schedule using recommended grease types.
  
• Inspect pivot joints periodically for early signs of wear.
  
• Avoid overloading the machine or abrupt impacts that stress pivot joints.
  
• Use protective seals or covers to prevent dirt ingress.
  
• Replace bushings proactively if moderate wear is detected.
  

Safety and Operational Considerations
Slack in pivot bushings can cause jerky movements, reduced precision, and accelerated wear in related components, increasing risk of mechanical failure or accidents. Timely maintenance and correct repair procedures help ensure safe, smooth operation and extend machine service life.
Summary Checklist for Taking Up Slack in Hough 65 Pivot Bushings

• Inspect pivot area for visual wear and play.
  
• Measure pin-to-bushing clearance.
  
• Determine if adjustment or replacement is needed.
  
• Remove worn bushings with appropriate tools.
  
• Machine pivot housing if necessary.
  
• Install new bushings or sleeves precisely.
  
• Apply proper lubrication.
  
• Reassemble and adjust pivot pins or fasteners.
  
• Test for eliminated slack and smooth movement.
  
• Schedule regular maintenance to prevent recurrence.
  

Taking proactive steps to address pivot bushing slack enhances the reliability and control of heavy equipment such as the Hough 65 loader, ensuring productive and safe operations over the long term.