Restoring the Sleeper on a Kenworth W900A

[MikePhua]

The Kenworth W900A and Its Long-Hood Legacy
The Kenworth W900A, introduced in the early 1970s, quickly became an icon of American long-haul trucking. Known for its extended hood, robust frame, and modular design, the W900A was favored by owner-operators who valued customization and mechanical simplicity. By the early 1980s, Kenworth had sold tens of thousands of W900A units across North America, with many still in service today, often restored or modified by enthusiasts.
Kenworth, founded in 1923 in Seattle, built its reputation on durability and driver comfort. The W900A series offered multiple sleeper configurations, including the sought-after 36-inch coffin bunk—a compact, aerodynamic sleeper that allowed for rest without sacrificing payload length.
Terminology Annotation

• Coffin Bunk: A narrow sleeper cab, typically 36 inches deep, mounted behind the truck cab for resting space.
  
• Tag Axle: An unpowered axle added behind the drive axles to increase load capacity and distribute weight.
  
• Riveted Plate: A metal panel fastened to the cab using rivets, often used to seal openings or reinforce structure.
  
• Large Opening: Refers to the size of the cutout between the cab and sleeper, affecting access and airflow.
  

Challenges in Finding a Replacement Sleeper
Restoring a W900A to its original sleeper configuration can be difficult. Many trucks from the 1980s had their bunks removed to install tag axles or shorten wheelbase for specialized hauling. Once removed, the sleeper units were often scrapped or repurposed, making original coffin bunks rare.
Operators seeking replacements face several obstacles:

• Limited availability due to age and scrappage.
  
• Regional scarcity, with most surviving units located in the western United States.
  
• Compatibility issues with cab openings and mounting brackets.
  
• Shipping logistics for oversized components.
  

In one case from Missouri, a restorer tracked down a sleeper in Oregon, willing to pay for cross-country freight just to complete the restoration. This level of commitment reflects the cultural value placed on preserving vintage rigs.
Identifying the Correct Sleeper Type
Kenworth offered both crawl-through and sit-in sleeper configurations. The distinction lies in the cab-to-sleeper opening:

• Crawl-Through: Small opening, typically used with narrow bunks.
  
• Sit-In: Large opening, allowing the driver to sit upright or move freely between cab and sleeper.
  

Determining the original configuration requires examining the cab’s rear wall. If a large portion is covered by a riveted plate or window insert, it likely had a sit-in sleeper. Kenworth’s factory records can confirm original specs, including sleeper size and mounting style.
Restoration Strategy and Fabrication Tips
When an original sleeper cannot be sourced, fabricators may build a replica using aluminum panels and vintage hardware. Key considerations include:

• Matching the curvature and rivet pattern of the original cab.
  
• Ensuring structural integrity for highway use.
  
• Installing insulation and ventilation for comfort.
  
• Recreating period-correct interior trim and lighting.
  

Some restorers salvage bunks from wrecked trucks or modify sleepers from similar models like the Peterbilt 359 or Freightliner FLD. While not identical, these can be adapted with custom mounts and trim.
Legal and Registration Considerations
In some jurisdictions, modifying the cab or adding a sleeper requires inspection and registration updates. This is especially true if the truck’s gross vehicle weight rating (GVWR) changes due to axle modifications or sleeper additions.
Recommendations include:

• Consulting with local DOT offices before installation.
  
• Documenting all structural changes and part sources.
  
• Verifying that sleeper dimensions comply with bridge law and length restrictions.
  

Anecdote from the Restoration Community
In Indiana, a retired driver restored his 1982 W900A with a factory-style sleeper sourced from a salvage yard in Ohio. The sleeper had been removed decades earlier and stored in a barn. After sandblasting, repainting, and reupholstering, the bunk was reinstalled with period-correct brackets and trim. The truck now serves as a showpiece at regional truck meets, drawing admiration from younger drivers unfamiliar with the coffin bunk era.
Recommendations for Enthusiasts and Builders

• Use factory records to confirm original sleeper specs.
  
• Network with restoration forums and vintage truck clubs.
  
• Consider fabricating a replica if sourcing proves impossible.
  
• Prioritize structural safety and weatherproofing.
  
• Preserve original mounting points when possible.
  

Closing Reflections
The coffin bunk on a Kenworth W900A is more than a sleeping compartment—it’s a symbol of a bygone era in trucking. Restoring or replacing it requires patience, resourcefulness, and a deep appreciation for mechanical heritage. Whether sourced from a distant salvage yard or built from scratch, the sleeper completes the silhouette of the classic long-nose Kenworth, honoring the legacy of drivers who lived life on the road, one mile at a time.