Solving Twisted and Binded Hydraulic Hoses at the Swivel Joint

[MikePhua]

The Role of the Swivel in Hydraulic Routing
In excavators and other tracked machines, the swivel joint—also known as the rotary manifold or center joint—is a critical component that allows hydraulic fluid to pass between the upper structure and the undercarriage while enabling continuous rotation. It feeds travel motors, blade cylinders, and auxiliary functions through a series of stacked channels and ports. These ports connect to hoses that must flex and rotate without binding, kinking, or twisting.
When hoses become twisted or bind at the swivel, it can lead to restricted flow, premature wear, and even catastrophic failure. This issue is especially common in machines that have undergone recent hose replacement, undercarriage work, or have been operated in muddy or debris-laden environments.
Symptoms of Hose Binding and Twisting
Operators and technicians may observe:

• Travel motors losing power or responding sluggishly
  
• Hoses rubbing against each other or the frame
  
• Visible twisting or spiraling of hoses near the swivel base
  
• Hydraulic leaks at crimped ends or fittings
  
• Audible popping or snapping sounds during rotation
  
• Increased heat in the affected circuit due to restricted flow
  

In one case, a contractor in Manitoba noticed his excavator would veer left during travel. Inspection revealed that two hoses feeding the right motor were twisted and partially collapsed, starving the motor of pressure.
Root Causes of Hose Twisting at the Swivel
Several factors contribute to this issue:

• Improper hose routing during installation
  If hoses are not aligned with their natural bend radius or are forced into position, they may twist under rotation.
  
• Incorrect clamp placement or missing guides
  Hose clamps and guides are designed to maintain spacing and prevent rotation-induced stress. Missing or misaligned clamps allow hoses to wander.
  
• Swivel rotation during hose installation
  If the upper structure is rotated while hoses are being connected, residual torque can remain in the hose body.
  
• Use of non-rotation-rated hoses
  Some hydraulic hoses are not designed to tolerate torsional stress and will fail prematurely if used in swivel applications.
  
• Debris buildup or frozen mud
  Accumulated material around the swivel can push hoses out of alignment or restrict movement.
  

Inspection and Correction Strategy
To resolve twisted or binded hoses:

• Rotate the upper structure slowly and observe hose movement
  
• Disconnect affected hoses and allow them to relax to their neutral position
  
• Reconnect hoses with the upper structure centered and swivel ports aligned
  
• Replace any hose showing signs of internal collapse or external abrasion
  
• Install or adjust hose clamps and guides to maintain spacing
  
• Use hoses with high-flex and torsion-rated specifications for swivel circuits
  

If hoses are severely twisted, they may need to be replaced entirely. Reusing a hose that has been stressed can lead to internal delamination and unpredictable failure.
Preventive Measures and Installation Best Practices
To prevent future issues:

• Always install hoses with the machine in its neutral position
  
• Use color-coded or labeled hoses to ensure correct port matching
  
• Avoid over-tightening clamps, which can restrict hose movement
  
• Clean the swivel area regularly to prevent debris interference
  
• Use protective sleeves or spiral wrap to reduce abrasion
  
• Document hose routing during major service for future reference
  

Some technicians use zip-tied foam spacers between hoses during installation to maintain spacing until permanent clamps are secured.
A Story from the Field
In 2022, a pipeline crew in Alberta experienced repeated travel faults on a mid-size excavator. After replacing the swivel seals, they noticed the travel hoses were binding and twisting during rotation. A field mechanic discovered that the upper structure had been rotated 90 degrees during hose installation, leaving residual torque in the lines. After re-routing the hoses with the house centered and installing new clamps, the issue disappeared. The crew later added a laminated routing diagram to their service binder to prevent recurrence.
Conclusion
Twisted and binded hoses at the swivel joint are more than a nuisance—they compromise hydraulic performance, increase wear, and pose safety risks. By respecting hose dynamics, aligning components during installation, and maintaining clean routing practices, technicians can ensure smooth rotation and reliable operation. In hydraulic systems, flexibility is strength—but only when it’s properly guided. When hoses flow freely, so does the machine.