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The Legacy of the JLG 60H
The JLG 60H is a hydraulic boom lift introduced in the late 1980s as part of JLG Industries’ push to expand its high-reach access equipment portfolio. JLG, founded in 1969 in McConnellsburg, Pennsylvania, quickly became a dominant force in aerial work platforms. By the time the 60H was released, JLG had already established a reputation for rugged, field-serviceable machines that could handle demanding construction and industrial tasks.
The 60H featured a 60-foot platform height, two-wheel drive, and a hydraulic steering system. It was powered by a gasoline or diesel engine, depending on configuration, and used a three-lever control system for boom, drive, and steer functions. Though production numbers for the 60H are not publicly available, JLG’s boom lift sales in the 1990s exceeded 10,000 units annually, with the 60H contributing to that volume.
Symptoms of Drive Wheel Interruption During Steering
A recurring issue reported with aging JLG 60H units is the sudden cessation of drive wheel movement when the steering switch is activated. This results in a jarring halt, especially noticeable during platform maneuvering. The problem is particularly perplexing because the drive system appears functional until steering input is introduced.
Operators have described the experience as follows:
This issue typically stems from electrical or hydraulic interlock failures. The JLG 60H uses a series of safety interlocks and logic circuits to prevent simultaneous conflicting operations. When these systems malfunction, they can inadvertently disable drive functions during steering.
Key diagnostic areas include:
Solutions and Preventive Measures
To resolve and prevent this issue, several steps can be taken:
As aerial lifts age, electrical and hydraulic systems become increasingly prone to failure due to environmental exposure, vibration, and wear. In 2022, a construction firm in Ohio reported that 30% of their older boom lifts experienced intermittent control issues, with steering-related faults being the most common. The firm implemented a preventive maintenance program focused on wiring harnesses and hydraulic valve calibration, reducing downtime by 40%.
In another instance, a rental company in Alberta retrofitted their fleet of JLG 60H units with upgraded control boxes sourced from newer models. The retrofit cost approximately $1,200 per unit but eliminated recurring drive interruptions and improved operator confidence.
Conclusion
The JLG 60H remains a workhorse in the aerial lift world, but its aging control systems can introduce frustrating quirks like drive wheel stoppage during steering. By understanding the interplay between electrical signals, hydraulic flow, and safety interlocks, technicians can diagnose and resolve these issues effectively. Preventive maintenance, targeted upgrades, and attention to grounding and solenoid performance are key to keeping these machines reliable in the field. As with any legacy equipment, the path to longevity lies in respecting its design while adapting to modern expectations.
The JLG 60H is a hydraulic boom lift introduced in the late 1980s as part of JLG Industries’ push to expand its high-reach access equipment portfolio. JLG, founded in 1969 in McConnellsburg, Pennsylvania, quickly became a dominant force in aerial work platforms. By the time the 60H was released, JLG had already established a reputation for rugged, field-serviceable machines that could handle demanding construction and industrial tasks.
The 60H featured a 60-foot platform height, two-wheel drive, and a hydraulic steering system. It was powered by a gasoline or diesel engine, depending on configuration, and used a three-lever control system for boom, drive, and steer functions. Though production numbers for the 60H are not publicly available, JLG’s boom lift sales in the 1990s exceeded 10,000 units annually, with the 60H contributing to that volume.
Symptoms of Drive Wheel Interruption During Steering
A recurring issue reported with aging JLG 60H units is the sudden cessation of drive wheel movement when the steering switch is activated. This results in a jarring halt, especially noticeable during platform maneuvering. The problem is particularly perplexing because the drive system appears functional until steering input is introduced.
Operators have described the experience as follows:
- Drive wheels operate normally until the steering switch is engaged.
- Upon steering input, the wheels abruptly stop, as if braking were applied.
- The engine may fail to throttle up during steering, compounding the issue.
- The control levers appear functional and have been previously replaced.
- Drive Wheels: The wheels powered by the engine to move the lift.
- Steering Switch: The electrical or hydraulic control that activates the steering function.
- Throttle Up: Increase in engine RPM to provide additional power during load or movement.
This issue typically stems from electrical or hydraulic interlock failures. The JLG 60H uses a series of safety interlocks and logic circuits to prevent simultaneous conflicting operations. When these systems malfunction, they can inadvertently disable drive functions during steering.
Key diagnostic areas include:
- Platform Control Wiring: Corroded or loose connectors at the platform can interrupt signal continuity. Wiggle testing may reveal intermittent faults.
- Steering Solenoid Malfunction: A faulty solenoid may draw excessive current or trigger a safety interlock, cutting drive power.
- Throttle Control Circuit: If the engine fails to throttle up during steering, the system may interpret this as a fault and disable drive.
- Hydraulic Flow Priority Valve: Some models use a priority valve to direct hydraulic flow. If steering demands override drive flow, movement may halt.
Solutions and Preventive Measures
To resolve and prevent this issue, several steps can be taken:
- Inspect and Clean Connectors: Use dielectric grease and contact cleaner on all platform and base connectors.
- Test Solenoids Under Load: Use a clamp meter to measure current draw during activation. Replace solenoids that exceed rated amperage.
- Verify Ground Integrity: Check all ground paths with a multimeter. Resistance should be near zero.
- Update Control Logic: If possible, retrofit with newer control modules that offer better fault tolerance.
- Hydraulic System Flush: Contaminated fluid can cause valve sticking. Replace filters and flush with manufacturer-recommended fluid.
- Dielectric Grease: A non-conductive lubricant that protects electrical connections from moisture and corrosion.
- Clamp Meter: A tool that measures electrical current without breaking the circuit.
- Fault Tolerance: The ability of a system to continue operating despite errors or failures.
As aerial lifts age, electrical and hydraulic systems become increasingly prone to failure due to environmental exposure, vibration, and wear. In 2022, a construction firm in Ohio reported that 30% of their older boom lifts experienced intermittent control issues, with steering-related faults being the most common. The firm implemented a preventive maintenance program focused on wiring harnesses and hydraulic valve calibration, reducing downtime by 40%.
In another instance, a rental company in Alberta retrofitted their fleet of JLG 60H units with upgraded control boxes sourced from newer models. The retrofit cost approximately $1,200 per unit but eliminated recurring drive interruptions and improved operator confidence.
Conclusion
The JLG 60H remains a workhorse in the aerial lift world, but its aging control systems can introduce frustrating quirks like drive wheel stoppage during steering. By understanding the interplay between electrical signals, hydraulic flow, and safety interlocks, technicians can diagnose and resolve these issues effectively. Preventive maintenance, targeted upgrades, and attention to grounding and solenoid performance are key to keeping these machines reliable in the field. As with any legacy equipment, the path to longevity lies in respecting its design while adapting to modern expectations.
