Friction Clutch Slippage in the Link-Belt LS-58 and How Operators Tackle It

[MikePhua]

The Link-Belt LS-58 and Its Mechanical Heritage
The Link-Belt LS-58 is a classic friction crane built for durability and simplicity. Manufactured during an era when mechanical systems ruled over electronics, the LS-58 became a favorite among operators in logging, dragline, and clamshell applications. With a manually operated clutch and brake system, the LS-58 relies on friction linings and drum contact to transmit power—a design that demands both mechanical precision and operator finesse.
Unlike modern hydraulic cranes, friction rigs like the LS-58 require constant adjustment, awareness of wear patterns, and a deep understanding of clutch behavior. These machines are still used today by enthusiasts and small contractors, often for personal projects or niche tasks where their simplicity is an asset.
Symptoms of Slipping Frictions
One of the most common issues with the LS-58 is clutch slippage during forward travel, especially under load or when climbing slopes. Operators report that:

• The crane moves fine on level ground but slips when turning or ascending
  
• Swing and hoist functions remain unaffected
  
• The clutch drum is clean, with only minor grooves
  
• New friction linings have been installed but have less than 10 hours of use
  

This suggests that the issue is not contamination or gross mechanical failure, but rather a combination of break-in behavior, lining material characteristics, and possibly clutch shoe orientation.
Terminology Clarification

• Friction Clutch: A mechanical device that transmits torque by pressing friction material against a rotating drum.
  
• Clutch Shoe: The curved component lined with friction material that engages the drum.
  
• Drum: The rotating surface against which the clutch shoes press to transmit motion.
  
• Break-In Period: The initial hours of operation after installing new linings, during which surfaces conform and friction improves.
  

Break-In and Material Behavior
New clutch linings—especially modern woven materials that lack asbestos—often require a longer break-in period. Unlike older linings that gripped aggressively from the start, newer materials are designed to wear in gradually, reducing drum scoring and extending life. However, this means that performance may be poor until the surfaces mate properly.
Operators suggest:

• Running the crane under light load for extended periods to accelerate break-in
  
• Avoiding steep slopes or heavy pulls during the first 20–30 hours
  
• Keeping the clutch adjusted tightly but not overly aggressive
  

Old-School Remedies and Field Wisdom
Veteran operators have long relied on unconventional methods to improve clutch performance. These include:

• Tossing a handful of pine rosin powder into the drum to increase grip
  
• Using baby powder to reduce grabby clutch behavior
  
• Applying Fuller’s Earth to absorb oil contamination
  
• Sprinkling sugar into the drum to create a sticky surface under heat
  
• In one legendary case, an operator threw a peanut butter and jelly sandwich into the swing friction—an act of desperation that became folklore
  

While these methods are not recommended for long-term maintenance, they reflect the ingenuity and improvisation common in friction crane operation.
Clutch Shoe Orientation and Directional Engagement
Another critical factor is the orientation of the clutch shoes. On friction rigs, the direction in which the shoes are installed affects engagement:

• Toe-to-heel orientation for clockwise rotation
  
• Heel-to-toe for counterclockwise rotation
  

If shoes are reversed—intentionally or accidentally—they may work fine for swing but fail during travel, especially on non-independent machines where the same drum serves multiple functions.
Operators should verify:

• Correct shoe orientation based on drum rotation
  
• That shoes are not mismatched or unevenly worn
  
• That springs and linkages are intact and properly tensioned
  

Hydraulic Assist and Valve Adjustment
Some LS-58 units feature hydraulic assist for clutch engagement. If the clutch slips despite proper mechanical setup, the issue may lie in hydraulic pressure:

• A broken spring in the dash-mounted control valve may prevent full spool engagement
  
• The adjustment screw may have backed off, reducing pressure
  
• The cup that depresses the spool should sit flush with the valve body
  

To inspect:

• Exhaust system pressure and remove the valve stop
  
• Remove the cup and check the spring for damage
  
• Reassemble and adjust the screw to restore full engagement
  

Conclusion
Friction clutch slippage in the Link-Belt LS-58 is a multifaceted issue that blends mechanical setup, material science, and operator technique. Whether it’s a matter of break-in time, shoe orientation, or hydraulic pressure, the solution often lies in careful inspection and a bit of old-school ingenuity. These machines may be relics, but they continue to teach valuable lessons in mechanical discipline and field problem-solving. With patience and attention to detail, even a slipping LS-58 can be brought back to full pulling power.