JLG 60H Low Hydraulic Pressure Issue and Equipment Overview

[MikePhua]

Machine Introduction
The JLG 60H is a versatile articulating boom lift designed for industrial, construction, and maintenance applications requiring elevated work platforms with reach capabilities up to 60 feet. It features a diesel engine, 4-wheel drive, oscillating axle, and hydraulic systems engineered for safe, smooth, and stable lifting.
Hydraulic System Specifications

• Hydraulic fluid reservoir capacity: Approximately 30.6 gallons (115.8 liters)
  
• Hydraulic system operating pressure: High enough to perform boom, jib, and platform lift functions smoothly under load
  
• Power source options include a diesel engine (Deutz TD2.9L4 Tier 4, 49 hp) or dual-fuel engines (GM Vortec 3000 MPFI, 82 hp)
  
• Auxiliary power: 12V DC system for controls and accessories
  
• Hydraulic system includes proportional controls for smooth operator inputs
  

Low Hydraulic Pressure Symptoms and Causes

• Reduced lift speed or failure to maintain platform height under load
  
• Erratic boom movements or inability to swing completely
  
• Loss of hydraulic pressure could be caused by:
  • Hydraulic fluid leaks or contamination reducing system pressure
    
  • Faulty hydraulic pumps or motor failures
    
  • Blocked or clogged hydraulic filters or passages
    
  • Worn or damaged hydraulic valves causing pressure drops
    
  • Air entrainment in the hydraulic fluid from leaks or insufficient fluid levels
    
  • Sensor or control system malfunctions impacting hydraulic pump output
    

Diagnostic and Repair Recommendations

• Check hydraulic fluid level and quality; replace or top-up with OEM-approved fluids if necessary
  
• Inspect the entire hydraulic circuit for leaks including hoses, fittings, and seals
  
• Replace or clean hydraulic filters regularly to avoid blockages
  
• Test hydraulic pump pressure and flow against manufacturer specifications
  
• Verify electronic sensors and control modules are functioning correctly; inspect wiring harnesses for damage
  
• Bleed the hydraulic system to remove air and restore proper pressure
  
• Consult the JLG service manual for specific pressure and flow testing procedures and tolerances
  

Terminology

• Hydraulic Pressure: The force exerted by fluid within the hydraulic system, measured in psi or kPa
  
• Articulating Boom Lift: A lift with jointed sections allowing access around obstacles
  
• Proportional Controls: Controls enabling smooth modulation of hydraulic movements in response to operator input
  
• Oscillating Axle: Allows wheels to move up/down independently to maintain traction and stability on uneven terrain
  
• Hydraulic Pump: Device moving hydraulic fluid under pressure to power actuator functions
  

Summary
Low hydraulic pressure on the JLG 60H boom lift can severely affect lifting performance and operator safety. This condition usually arises from hydraulic leaks, pump or valve wear, contamination, or control system faults. Systematic inspection covering fluid condition, circuit integrity, filters, pumps, and sensors is essential to diagnose and rectify the problem efficiently. Routine maintenance following manufacturer guidelines helps prevent hydraulic pressure issues and promotes reliable boom lift operation at job sites.