Getting a Link-Belt LS-98 Crane to Travel Again

[MikePhua]

The Link-Belt LS-98 and Its Mechanical Legacy
The Link-Belt LS-98 cable crane was a staple of mid-20th-century lifting and excavation work, particularly in marine, pile-driving, and clamshell operations. Manufactured by Link-Belt, a company with roots dating back to 1874, the LS-98 was part of a long lineage of lattice boom cranes known for mechanical simplicity and rugged durability. Powered by the International UD-18 diesel engine, the LS-98 was often deployed on barges, docks, and job sites where hydraulic systems were still considered a luxury.
Unlike modern hydraulic cranes, the LS-98 relied on mechanical clutches, jaw couplings, and brake levers to control swing, hoist, and travel. Its Speedomatic control system—hydraulic assist for mechanical linkages—was a transitional technology that allowed smoother operation without full hydraulic conversion.
Terminology Clarification

• Travel Dawgs: Mechanical locks that prevent the crawler tracks from engaging unintentionally.
  
• Master Clutch: A primary clutch that engages the engine to the drive system; must be activated to power any function.
  
• Jaw Clutch: A toothed coupling that engages drive shafts; used for travel and swing functions.
  
• Swing Brake: A mechanical brake that locks the upper structure from rotating.
  
• Accumulator: A hydraulic pressure reservoir that stabilizes clutch engagement in Speedomatic systems.
  

Why the LS-98 May Refuse to Move
When an LS-98 sits idle for years—especially on a barge or uneven terrain—its mechanical systems can become stiff, misaligned, or simply misunderstood. Common reasons for travel failure include:

• Travel dawgs still engaged, preventing drive chain tension.
  
• Master clutch not engaged, leaving the drive system disconnected.
  
• Incorrect sequence of travel brake and clutch levers.
  
• Swing/travel selector lever stuck between modes.
  
• Hydraulic accumulator low on pressure, causing weak clutch actuation.
  
• Rusted or seized jaw clutches due to long-term inactivity.
  

In one case, an LS-98 that had been used for clamshell dredging on Lake Winnipesaukee was brought ashore and refused to travel. The engine ran fine, and the swing function barely worked, but the tracks wouldn’t engage. After careful inspection, it became clear that the operator hadn’t fully disengaged the travel brakes or properly shifted the swing/travel selector.
Correct Lever Sequence for Travel Engagement
To move the LS-98 under its own power, the operator must follow a precise sequence:

• Engage the master clutch using the long floor-mounted lever to the left of the seat.
  
• Release both travel brake levers (typically third and fourth from the left on the console).
  
• Engage the travel clutch lever (second from the left) for forward or reverse motion.
  
• Ensure the swing/travel selector lever—located behind the operator’s right shoulder—is set to travel mode.
  
• If equipped, set the high/low travel speed lever to low to avoid shaft damage.
  

Turning is achieved by releasing only one travel brake and engaging the travel clutch, causing one track to move while the other remains stationary.
Swing System Troubleshooting
If the crane struggles to swing, check the following:

• Swing brake may be engaged—located under the rear center of the upper frame.
  
• Swing lock lever near the gauge console may be set.
  
• Hydraulic accumulator may need recharging—pressure bumps in the hose every 10 seconds suggest low charge.
  
• Swing clutch may be misaligned or seized from inactivity.
  

A properly functioning swing system should allow the house to rotate freely when brakes are released. If the machine is sitting on a slope, the counterweight may resist rotation uphill, requiring more clutch force.
Restoration Tips for Long-Idle Units
For cranes that haven’t moved in years:

• Inspect all clutch linkages for rust and stiffness.
  
• Lubricate jaw couplings and check for alignment.
  
• Recharge or replace the hydraulic accumulator.
  
• Drain and replace hydraulic fluid with OEM-spec oil.
  
• Line bore swing and travel vertical shafts if excessive play is found.
  
• Avoid shifting into high travel speed unless absolutely necessary—many shafts were stripped by inexperienced operators.
  

In Georgia, a crane rebuilder noted that running LS-98s in high travel speed often led to catastrophic shaft failure. He recommended permanently locking the machine in low gear unless operated by a trained crew.
A Story from the Field
In Washington State, a crane enthusiast rescued three LS-98s from scrap yards. One had been stripped to the frame rails and rebuilt with new bearings, seals, and line-bored bores. After restoring the swing and travel systems, he used the crane for lifting logs and setting flagpoles. His experience proved that even machines headed for the shear could be revived with patience and mechanical know-how.
Conclusion
Getting a Link-Belt LS-98 to travel again requires more than just engine power—it demands a deep understanding of its mechanical control logic, clutch sequencing, and hydraulic assist systems. With careful inspection, proper lever operation, and a bit of restoration work, these vintage cranes can still perform the tasks they were built for decades ago. As more of these machines disappear into scrap, preserving their functionality becomes both a technical challenge and a tribute to the era of cable-operated iron.