Understanding and Adjusting the Track Adjuster Grease Block on a Caterpillar 315BL Excavator

[MikePhua]

Introduction to Track Adjuster Grease Blocks
The track adjuster grease block is an essential component in the undercarriage system of tracked excavators like the Caterpillar 315BL. It facilitates the proper tensioning of the track by housing grease fittings and relief valves that allow controlled injection and release of hydraulic grease to adjust the track’s idler position. Proper alignment and functioning of this grease block are crucial for maintaining track tension, preventing excessive track wear, and ensuring smooth machine operation.
This article explores the positioning challenges of the grease block on the Cat 315BL, offers detailed troubleshooting and adjustment steps, highlights common issues, and provides practical advice backed by industry experience to help operators and technicians effectively maintain and service this component.

Grease Block Function and Configuration

• The grease block is usually a square or rectangular housing attached near the idler assembly, containing:
  • Grease fitting: The port where grease is injected using a grease gun.
    
  • Relief valve bolt: Allows excess grease and pressure to escape to prevent over-tightening.
    
• The block is responsible for transferring grease pressure to the track adjuster cylinder, which moves the idler to maintain track tension.
  
• It is critical that the grease block is correctly aligned with its framed opening on the excavator frame to allow convenient access to the grease fitting and relief valve for maintenance.
  

Challenges in Grease Block Alignment on Cat 315BL

• On certain Cat 315BL machines, the grease block may become misaligned, pointing downward at an angle rather than being squared with the frame opening.
  
• This misalignment complicates access to the grease fitting and relief bolt, making grease application and pressure relief procedures cumbersome.
  
• Attempts to manually twist or move the grease block with slight pressure often fail due to mechanical restraints or the design of the idler assembly.
  
• The track must be loosened and separated to facilitate some degree of movement or servicing of the grease block assembly.
  

Steps to Adjust or Service the Grease Block

1. Loosen the Track and Separate it if Needed:
   • Before attempting grease block adjustment, the track must be loosened adequately to relieve tension.
     
   • Separating the track (breaking the track chain) provides more freedom to maneuver components for better access.
     
2. Inspect the Idler Assembly and Mounting:
   • The grease housing/block is fixed to the idler assembly.
     
   • Check if the idler assembly needs to be removed or shifted within the slide rails to reposition the grease block for easier access.
     
   • On some models, removing the idler assembly from the slides is necessary to fully realign the grease block.
     
3. Check for Obstructions or Retaining Mechanisms:
   • Investigate if any retaining pins, bolts, or brackets hold the grease housing in a fixed orientation.
     
   • Removing or loosening these can permit repositioning of the grease block to align with access openings.
     
4. Align and Re-secure the Grease Block:
   • Rotate or adjust the grease housing so the grease fitting and relief valve align squarely with the framed access openings on the excavator frame.
     
   • Tighten any mounting hardware securely to prevent future misalignment.
     
5. Perform Grease Injection and Pressure Relief:
   • With proper alignment, apply grease through the fitting.
     
   • Observe pressure and periodically loosen the relief valve bolt if pressure builds excessively, avoiding hydraulic overload on the track adjuster cylinder.
     
6. Reassemble and Test Track Tension:
   • Once servicing is complete, reassemble the track and tighten it according to manufacturer specifications.
     
   • Test the track tension adjustment function to confirm proper operation.
     

Additional Tips and Solutions

• Use Proper Tools: Employ suitable sockets and wrench sizes to access relief bolts easily, considering that some bolts may be tight or corroded.
  
• Preventive Alignment Checks: Regularly inspect track adjuster grease block alignment during routine maintenance to avoid access issues.
  
• Lubrication Frequency: Adhere to lubrication schedules to prevent excessive filler pressure and potential housing distortion.
  
• Cleaning Before Servicing: Remove dirt and debris around the grease block to ensure clear access and prevent contamination.
  
• Consult Parts Catalogues: Reference the Cat 315BL parts book or service manual to understand the grease block assembly configuration and identify related components.
  

Terminology Explained

• Track Adjuster: Mechanism maintaining proper track tension by moving the idler forward or backward hydraulically or via grease pressure.
  
• Grease Block (Housing): Component housing grease fittings and relief valves controlling grease flow to the adjuster.
  
• Relief Valve Bolt: A bolt that can be loosened to release excess grease pressure during adjustment.
  
• Idler Assembly: The wheel assembly that guides and supports the track; movement of the idler changes track tension.
  
• Frame Opening: The structural cut-out in the excavator’s undercarriage frame enabling access to grease fittings and bolts.
  
• Slide Rails: Structural channels in which the idler assembly moves during track adjustment.
  

Real-World Anecdotes and Practical Experience

• One Caterpillar 315BL operator recounted a scenario where an initially tight and awkward grease fitting was resolved by fully loosening the track and removing the idler assembly slightly, which then allowed the grease block to be rotated and accessed easily.
  
• Another maintenance technician shared that on some machines, blocked or sealed grease fittings led to excessive pressure, causing the grease block to shift or deform slightly, complicating future servicing; replacing worn seals and frequent lubrication prevented recurrence.
  
• In heavy excavation projects, crews emphasized that addressing grease block access issues during scheduled downtime avoided on-site breakdowns caused by improper track tension.
  

Summary
The track adjuster grease block on the Caterpillar 315BL excavator is a critical yet sometimes challenging component to service, especially when misaligned and difficult to access. Successful servicing requires understanding its relationship with the idler assembly and track looseness, often necessitating partial disassembly for repositioning.
Proper alignment ensures smooth grease fitting access and pressure relief valve operation, vital for correctly adjusting track tension and prolonging undercarriage life. Using the right tools, following maintenance routines, and consulting service documentation improve the efficiency and reliability of this procedure.
Real-world experiences suggest that loosening or temporarily removing the idler assembly allows effective grease block repositioning. Regular inspections and preventive care reduce misalignment problems and maintain optimal track adjustment function, supporting safer and more productive excavator operation.
By following these detailed insights and solutions, operators and technicians can confidently address grease block alignment and servicing challenges on the Cat 315BL, enhancing machine uptime and undercarriage longevity.