Reviving a Long-Stored Caterpillar D6B Dozer

[MikePhua]

The D6B and Its Historical Footprint
The Caterpillar D6B was introduced in the 1960s as part of CAT’s mid-size dozer lineup, designed for grading, land clearing, and light earthmoving. With an operating weight of around 20,000 lbs and powered by the reliable CAT D333 engine, the D6B became a staple in agriculture, forestry, and construction. Its mechanical simplicity, robust undercarriage, and straightforward serviceability made it a favorite among owner-operators and rural contractors.
Caterpillar Inc., founded in 1925, built its reputation on machines like the D6 series. The D6B was produced during a time when hydraulic systems were becoming more common, but electronics had not yet entered the picture—making it a purely mechanical workhorse. Thousands were sold across North America, and many remain in barns, sheds, and fields, waiting for a second life.
Terminology Annotation
- Pony Motor: A small gasoline engine used to start the main diesel engine, common in older CAT machines before electric starters became standard.
- Undercarriage: The assembly of tracks, rollers, idlers, and sprockets that supports and propels a tracked machine.
- Block Gallery: An internal oil passage in the engine block used to distribute lubrication to bearings and moving parts.
- Electric Start Conversion: A retrofit or factory option replacing the pony motor with a direct electric starter system.
Assessing a Dozer After 30 Years of Storage
When a machine like the D6B has been parked indoors for three decades, several factors determine its viability:

• Was it stored dry and protected from rodents?
  
• Were fluids drained or left in place?
  
• Was the engine turned periodically to prevent sticking?
  

In this case, the dozer was parked in a shed and left untouched since the original owner passed away. The family is now clearing the property, and the machine is available—potentially at scrap value.
The absence of a pony motor is notable. Later D6Bs were offered with factory electric start, which eliminated the need for the high-RPM gasoline starter known for reliability issues. These “buzz bombs,” as some operators called them, were prone to failure and difficult to repair. Electric start simplifies revival efforts and reduces risk.
A Story from the Field
In Manitoba, a farmer inherited a D6B from his father-in-law. The machine had been parked in a barn since the late 1980s. Curious about its condition, he planned to bring a breaker bar and attempt to turn the engine manually. If the crankshaft rotated freely, he would prime the fuel system, install new batteries, and attempt a start.
Before doing so, he was advised to:

• Drain the engine oil and refill through the block gallery using a pressurized garden sprayer to pre-lube bearings
  
• Inspect the air intake for nests or debris
  
• Check fluid levels and look for signs of water intrusion
  
• Run fuel from a clean external jug to avoid contamination from the tank
  

These steps are essential to prevent damage during the first startup attempt.
Evaluating the Undercarriage and Structural Integrity
Even if the engine is stuck, the undercarriage may retain value. Track rails, pads, and rollers can be reused or sold if in good condition. A quick visual inspection of rail height, pad wear, and roller alignment can reveal whether the machine was parked with care.
In one case, a D6B with a frozen engine was salvaged for its undercarriage, which fit several other CAT models. The resale value of the tracks alone exceeded the scrap price of the entire machine.
Recommendations for Revival
To safely revive a long-stored dozer:

• Remove the injectors and fog the cylinders with penetrating oil
  
• Rotate the engine slowly by hand to check for binding
  
• Replace all filters and fluids before attempting a start
  
• Inspect hydraulic lines and cylinders for dry rot or corrosion
  
• Check brake and clutch linkages for freedom of movement
  
• Use a multimeter to test electrical continuity before installing batteries
  

If the engine turns and compression is present, odds of a successful start are high. However, expect leaks, seal failures, and minor electrical issues as part of the process.
Why Old Dozers Still Matter
In North America, the affection for vintage dozers runs deep. Unlike newer machines burdened with complex electronics and expensive diagnostics, older CATs offer mechanical transparency. They can be repaired with basic tools, and parts are often interchangeable across models.
For hobbyists and small landowners, restoring a D6B is not just about utility—it’s about preserving a legacy. These machines were built during an era of over-engineering, when durability trumped cost-cutting. Their continued existence is a testament to that philosophy.
Conclusion
Reviving a Caterpillar D6B after 30 years of dormancy is a challenge rooted in patience, mechanical intuition, and respect for history. With careful inspection, methodical preparation, and a bit of luck, these machines can roar back to life and serve for decades more. Whether used for grading a driveway or clearing a field, the satisfaction of restoring a classic dozer is unmatched—and the journey is often as rewarding as the destination.