Removing and Reinstalling the Swing Motor on a John Deere Backhoe

[MikePhua]

The Role of the Swing Motor in Backhoe Operation
The swing motor is a critical hydraulic component that enables the backhoe boom to pivot left and right. Mounted between the boom and the mainframe, it translates hydraulic pressure into rotational movement, allowing the operator to position the bucket precisely during trenching, loading, or cleanup. On John Deere backhoes, the swing motor is typically a rotary cylinder clamped between two large pins and secured by torque arms and mounting bolts.
Swing motors are subject to high stress and frequent directional changes, making them prone to seal wear and hydraulic leaks over time. A leak at the top of the motor often indicates a failed upper seal or shaft wear, requiring removal and repair.
Preparing for Swing Motor Removal
Before attempting removal, it’s essential to assess the mounting configuration. Many operators assume the large pins must be extracted, but in most cases, the swing motor is held in place by clamps and bolts that can be accessed without disturbing the pins.
Preparation steps:

• Park the machine on level ground and secure the boom
  
• Rotate the boom 90 degrees to expose the motor’s mounting bolts
  
• Disconnect hydraulic lines and cap them to prevent contamination
  
• Clean the area around the motor to avoid introducing debris during removal
  

Terminology:

• Torque arm: A linkage that stabilizes the swing motor and absorbs rotational stress
  
• Tapered sleeve: A conical insert that aligns and secures the torque arm bolt
  
• Rotary cylinder: A hydraulic actuator that produces rotational motion
  

Removing the Swing Motor Without Extracting Pins
On many John Deere models, the swing motor is clamped by upper and lower plates that grip splines on the motor shaft. These plates are bolted to the frame and can be removed independently of the side pins.
Removal procedure:

• Locate the four mounting bolts securing the motor clamps
  
• Loosen and remove the torque arm bolt, which may be tapered and require gentle tapping
  
• Inspect for alignment dowels around the mounting bolts
  
• Use threaded rod or all-thread studs to guide the motor out evenly
  

One technician used four 18-inch sections of ¾-inch all-thread inserted into the bolt holes to support the motor during removal. By threading nuts onto the rods and lowering them gradually, the motor was removed without tilting or binding.
Handling Alignment and Reinstallation
Reinstalling the swing motor requires precise alignment to ensure full swing range and prevent binding. The splined shaft must engage correctly with the upper and lower clamp plates, which are often keyed or indexed.
Reinstallation tips:

• Use all-thread studs as guide rails to slide the motor into position
  
• Align dowel pins before tightening bolts
  
• Torque mounting bolts to manufacturer specification (often around 350 ft-lbs)
  
• Reconnect hydraulic lines and bleed air from the system
  

Improper alignment can result in reduced swing range or premature wear. On some models, the upper and lower clamp plates are asymmetrical and must be oriented correctly to allow full boom travel.
Seal Replacement and Shaft Repair
If the leak originates from the top seal, the motor must be disassembled and the seal replaced. In cases of shaft scoring or pitting, spray welding or shaft polishing may be required.
Seal replacement steps:

• Remove the motor from the machine
  
• Disassemble the housing and extract the shaft
  
• Replace upper and lower seals with OEM-grade components
  
• Inspect bearings and replace if worn
  
• Reassemble and pressure test before installation
  

Spray welding involves applying a metal coating to the worn shaft and machining it back to specification. This technique restores sealing surfaces without replacing the entire shaft.
Safety and Lifting Considerations
Swing motors are heavy and awkward to handle. Use an engine hoist or hydraulic crane to support the motor during removal and installation. Avoid lifting by hand or using makeshift tools, as misalignment or dropped components can cause injury or damage.
Safety guidelines:

• Use rated lifting equipment with proper slings or chains
  
• Keep hands clear of pinch points during lowering
  
• Wear eye protection when tapping bolts or sleeves
  
• Confirm hydraulic pressure is relieved before disconnecting lines
  

One operator used an engine hoist and threaded rods to reinstall the motor with minimal effort, noting that the alignment dowels made final positioning straightforward.
Conclusion
Removing and reinstalling the swing motor on a John Deere backhoe is a manageable task with the right preparation and tools. By understanding the clamping system, avoiding unnecessary pin removal, and using threaded guides for alignment, operators can replace seals and restore swing function efficiently. In hydraulic systems, precision matters—and with careful handling, even the most stubborn leaks can be resolved without drama.