Retracting the Power Pin Fly on a Grove RT760 Crane

[MikePhua]

The Grove RT760 and Its Telescoping Boom System
The Grove RT760 is a rough terrain hydraulic crane manufactured by Grove, a brand under Manitowoc Company, Inc. Grove has been producing mobile cranes since the 1940s and is known for its robust designs and field serviceability. The RT760, part of Grove’s RT series, features a four-section telescoping boom with a maximum tip height exceeding 110 feet and a rated capacity of 60 tons. One of its key features is the hydraulic fly jib—often referred to as the “power pin fly”—which allows for extended reach and offset angles during lifting operations.
The fly jib is designed to be hydraulically pinned and retracted or extended depending on the lift configuration. While the extension process is straightforward, retracting the fly can present challenges, especially when the boom is at an angle or the becket line is not properly tensioned.
Terminology:

• Fly jib: An auxiliary boom extension mounted at the tip of the main boom
  
• Power pin fly: A hydraulically actuated fly jib that locks into position using powered pins
  
• Becket line: A rope or cable used to guide or restrain the fly during movement
  
• 0 degrees: Refers to the boom being horizontal, which reduces gravitational resistance
  

Why Retraction Can Be Difficult Without Proper Setup
Retracting the power pin fly requires aligning the boom and fly jib in a way that minimizes mechanical resistance. The ideal position is with the boom at or near 0 degrees, allowing the fly to slide back with minimal gravitational load. If the boom is elevated, the fly may bind or resist movement due to weight and misalignment.
In practice, operators often need a second piece of equipment—such as an extendable boom forklift or another crane—to assist in guiding or restraining the fly during retraction. This is especially true if the becket line cannot be anchored securely to the crane’s frame.
Common challenges:

• Fly binds due to boom angle or misalignment
  
• Hydraulic pins fail to disengage due to pressure imbalance
  
• Becket line lacks tension or anchoring point
  
• Operator lacks visibility or control over fly movement
  

Recommended Procedure for Safe Retraction
To retract the fly jib safely and efficiently:

• Lower the boom to as close to 0 degrees as possible
  
• Ensure the becket line is tied off securely to the crane’s frame or a stable anchor
  
• Use a second machine (e.g., forklift or telehandler) to guide the fly if necessary
  
• Engage hydraulic controls slowly to avoid sudden movement
  
• Monitor pin engagement and confirm full retraction before stowing
  

In one field operation, a crew used a skid-mounted winch to tension the becket line while lowering the boom. This allowed the fly to retract smoothly without binding, and the hydraulic pins engaged without issue.
Hydraulic Pin Systems and Maintenance Considerations
The power pin system relies on hydraulic pressure to engage and disengage locking pins that secure the fly in place. Over time, these systems can develop leaks, pressure loss, or contamination that affect performance. Regular inspection and maintenance are essential to ensure reliable operation.
Maintenance tips:

• Check hydraulic fluid levels and filter condition monthly
  
• Inspect pin cylinders for leaks or scoring
  
• Test pin engagement under load and during boom movement
  
• Lubricate pivot points and guide rollers as per manufacturer schedule
  

In one case, a crane failed to retract its fly due to a stuck hydraulic pin. The issue was traced to a contaminated fluid line that restricted pressure flow. Flushing the system and replacing the filter restored full function.
Training and Operator Awareness
Retracting the fly jib is a task that requires coordination, mechanical understanding, and situational awareness. Operators should be trained not only in control panel operation but also in the mechanical behavior of the boom and fly under different angles and loads.
Training recommendations:

• Simulate fly retraction during routine maintenance days
  
• Use visual aids to demonstrate pin alignment and fly movement
  
• Practice with a second machine to understand assisted retraction
  
• Document procedures and share lessons learned across crews
  

In one training session, a veteran operator demonstrated how improper boom angle caused the fly to twist during retraction, risking structural damage. The lesson emphasized the importance of geometry and tension control.
Conclusion
Retracting the power pin fly on a Grove RT760 crane is a nuanced operation that blends hydraulic control, mechanical alignment, and auxiliary support. While the system is designed for field efficiency, real-world conditions often require creative solutions and teamwork. With proper boom positioning, secure becket line anchoring, and attention to hydraulic pin behavior, the fly can be retracted safely and reliably. In crane operations, precision isn’t just about lifting—it’s about knowing how to bring every component home.