Understanding the Data Plate on a Caterpillar 426 Backhoe Loader

[MikePhua]

When you come across an older Caterpillar 426 Backhoe Loader on a job site or in a barn find, one of the most useful clues about the machine’s identity and configuration is its data plate. This metal plate, riveted on the frame near the operator’s station, carries coded information that tells you exactly what variant of the 426 you have, what engine and transmission it was built with, and how the machine was originally specified by Caterpillar. Interpreting these codes with confidence can save time when ordering parts, planning maintenance, or verifying authenticity.
What the Data Plate Tells You
On a Caterpillar backhoe loader like the 426, the data plate typically includes several lines of information. Reading these in context gives you a snapshot of the machine’s original build:

• Machine Model and Serial Number
  • The first line shows the machine model (e.g., 426) and the machine serial number (SN).
    
  • Next to the SN is an Arrangement Number, which is essentially a bill of materials code that describes the complete assembly makeup at the factory.
    
  • Example interpretation:
    • Model: 426
      
    • Serial Number: 7BC02306
      
    • Arrangement #: Identifies the exact factory build combination of options and components for that SN.
      
• Engine Information
  • The second line lists the engine serial number and its engine arrangement number.
    
  • The arrangement number here tells you what engine options or arrangements were installed (e.g., emissions configuration, accessory brackets).
    
• Transmission Information
  • The third line lists the transmission serial number and the transmission arrangement number.
    
  • This helps verify what gearbox and control options were fitted originally.
    

Rather than random strings of letters and digits, these are structured codes. The prefix (like “7BC”) often indicates the production series. Prefixes shift over time as Caterpillar updates models; machines built in the late 1980s through 1990s tend to have different prefixes than those from later decades.
Data Plate Terminology

• Serial Number (SN): Unique identifier for the machine. Think of it like a vehicle’s VIN.
  
• Arrangement Number: A code representing the exact combination of parts and configurations that went into that machine from the factory.
  
• Prefix: The first few characters in the serial number indicating series or production batch.
  
• Engine / Transmission Serial Numbers: Separate identifiers for major components, useful for part look-ups and service history.
  

Why This Matters
Accurately reading the data plate can prevent costly mistakes. For example, a 426 with a particular arrangement may use a different injection pump or hydraulic pump than another 426 built in a different series. Ordering parts without knowing the exact arrangement can lead to returns and downtime.
A vintage equipment collector once shared how a data plate saved a rare late-1980s 426 from being retrofitted incorrectly. The machine had sat idle for years, and the shop initially ordered a later-model hydraulic valve body that seemed to fit visually. Only after re-checking the data plate and arrangement number did they realize the original build used a discontinued component. Sourcing the correct unit restored performance without needless modification.
Caterpillar 426 in Context
The Caterpillar 426 backhoe loader has been a workhorse around farms, construction sites, and utility projects. It fits into Caterpillar’s lineup between smaller loaders like the 416 series and larger machines in the 430 range. The 426 has seen multiple iterations over decades, with improvements to operator comfort, hydraulics, and emissions compliance. Newer variants, including later Phase 2 side-shift models, offer more standardized components and improved serviceability.
Development History and Manufacturer Overview
Caterpillar Inc., founded in the early 20th century and headquartered in the United States, has long been a leader in heavy equipment. The company’s backhoe loaders gained prominence as versatile machines combining a front loader with a rear excavator, suitable for digging, loading, trenching, and landscaping. By the 1980s and 1990s, models like the 426 were widely adopted globally, with thousands sold across agriculture, construction, and rental fleets each year.
Plate Interpretation in Practice
To decode a data plate in the field:

• Locate the metal tag on the machine’s frame near the operator’s entrance.
  
• Write down each line exactly as printed.
  
• Break the serial numbers into prefix and numeric sequence.
  
• Reference parts catalogs or dealer database tools with the SN and arrangement numbers to identify original components.
  
• Use the engine and transmission serial numbers to pull service histories or confirm replacement parts.
  

Maintenance and Verification Tips
When evaluating a used 426:

• Cross-check the engine serial number on the data plate with the number physically stamped on the engine block. A mismatch could indicate engine replacement.
  
• Use catalog tools and dealer support to interpret arrangement numbers — dealers often have access to build sheets.
  
• For machines with high hours, verify the transmission and engine codes to ensure rebuilds or swaps used correct component variants.
  

Summary of Common Data Plate Fields

• Machine model designation
  
• Machine serial number (with prefix)
  
• Machine arrangement number
  
• Engine serial number
  
• Engine arrangement number
  
• Transmission serial number
  
• Transmission arrangement number
  

Proper interpretation of these fields provides confidence in parts selection, maintenance planning, and valuation.
In the world of heavy equipment, details matter. Knowing how to read a data plate turns a jumble of letters and numbers into a clear story about where the machine came from and how it was built. Accurate interpretation is a fundamental skill for owners, technicians, and restorers alike — and can mean the difference between a smooth restoration and a costly misstep.