Overview of the Caterpillar 235 Excavator

[MikePhua]

History and Development
The Caterpillar 235 is part of Cat’s 200-Series line, introduced in the early 1970s as Caterpillar expanded into full-size hydraulic excavators. The 235 was launched around 1973 to compete in the roughly 35-ton class sector. It was one of the foundational models that helped Cat establish its reputation in heavy excavators, complementing the 225 and later the 245 models. Over its production life, the 235 went through several series or “variants” (such as A, B, C, D) with incremental improvements in engine, hydraulic performance, undercarriage durability, and operator comfort. It was eventually phased out in favor of newer models with more modern emissions, more efficient hydraulics, and ergonomic improvements.
Key Specifications and Performance
Here are typical specifications for a Caterpillar 235 (varies depending on variant such as “B”, “C”, “D” etc.):

• Net Power: ~ 195 hp (≈ 145 kW) from a 6-cylinder CAT 3306 engine.
  
• Operating Weight: ~ 84,400 lbs (≈ 38,300 kg) for basic configurations. Some variants may be heavier with added attachments or wide track sets.
  
• Fuel Capacity: ~ 105 US gallons (≈ 397 liters).
  
• Hydraulic Flow: ~ 190 gallons/minute (≈ 720 liters/minute).
  
• Relief Valve Pressure: Approx. 1,000 psi (note: verify model variant, some heavy-duty attachments may require higher settings).
  

Dimensions and Reach
Depending on boom/stick configuration, the 235 can reach impressive working envelopes. Here are sample reach / digging metrics from different configurations:

• Max digging depth: ~ 22.5 to ~ 26.5 ft depending on boom/ stick length.
  
• Max reach along ground: 35 to nearly 39 ft in longer boom/stick options.
  
• Max cutting or loading height: in the low 30-ft range (30-33 ft) depending on configuration.
  

Physical dimensions:

• Width over tracks: approx. 11-12 ft depending on track width or gauge.
  
• Height to cab top: ~ 11 ft or slightly more in certain variants.
  
• Ground clearance, track gauge, shoe size, tail swing radius are variant dependent. Example: shoes ~ 30 in wide, tail swing ~ 11 ft in some cases.
  

Variants and Upgrades
The 235 line had several sub-models (B, C, D, etc.). These improvements included:

• Stronger undercarriage components for longer track life.
  
• More efficient hydraulic systems to improve speed and digging force.
  
• Options for longer sticks and booms to increase reach.
  
• Wide gauge or “wide track” versions for better stability and lower ground pressure, especially useful when working in soft or wet terrain.
  

Use, Durability and Known Issues
These machines are known to be tough. Many units built in the 1970s-80s are still in service when well maintained. But common wear issues reported are:

• Undercarriage wear: track shoes, rollers, idlers need periodic replacement.
  
• Hydraulic leaks: seals in boom, stick and bucket linkage, particularly in older machines.
  
• Engine maintenance: fuel, oil, cooling systems require care, especially in machines with many hours.
  

A seller ad from 1987 for a 235B showed an example with ~ 17,600 working hours with undercarriage reported at about 50 % remaining, which illustrates how the machine can last tens of thousands of hours with regular maintenance.
Applications
Typical uses for a 235 include:

• Large-scale excavation and earthmoving projects.
  
• Mining overburden removal.
  
• Quarrying tasks.
  
• Heavy foundation work, trenching with deep sticks.
  
• Forestry, especially when outfitted with forestry guarding or thumbs.
  

Small Story
A long-time operator in British Columbia once worked a 235C in a logging operation. He’d replaced the boom and stick seals several times over 20,000 hours of use. The machine was fitted with a wide gauge set of tracks to reduce ground pressure because the terrain was soft after heavy rains. Despite its age, the machine still dug out rock banks and loaded trucks, though speed was slower compared to newer excavators. The operator noted that fuel consumption went up by about 10-15 % in the later years, largely due to hydraulic inefficiency and worn boom linkage. When a local mine upgraded to newer machines, they offered the old 235 to the community at a discount; it took several months but eventually sold, showing there remains demand for these classic workhorses.
Recommendations for Buyers and Maintenance

• Always inspect the undercarriage: shoes, pins, bushings; replacing these can be expensive.
  
• Check hydraulic system for leaks, especially boom and stick cylinders. Old machines often have hard starts in cold or humid climates—inspect seals, pumps, fuel system.
  
• Evaluate boom/stick length and configuration — longer adds reach but also stress, possibly more maintenance.
  
• Verify operating hours and maintenance history. Units over ~ 15,000-20,000 hours still usable but expect higher maintenance costs.
  
• For transport: width, height, and weight make hauling expensive. Wide track or extended counterweights can increase dimensions.
  

Conclusion
The Caterpillar 235 excavator represents a durable, powerful class of hydraulic machinery with decades of work behind it. With ~ 195 hp, large fuel capacity, strong reach, and multiple variants, it was built for heavy digging and demanding environments. For operators willing to deal with the upkeep, it offers excellent value. For buyers, a well-maintained unit can be a smart investment; worn components and services are the usual cost trade-offs.