10-22-2025, 07:58 PM
CAT E120B Excavator Overview
The Caterpillar E120B is a mid-size hydraulic excavator introduced in the late 1980s and produced through the early 1990s. Designed for general excavation, trenching, and light demolition, it features a mechanical fuel injection system, open-center hydraulics, and a robust steel frame. Powered by a Mitsubishi 6D16 diesel engine rated at approximately 110 horsepower, the E120B weighs around 27,000 pounds and offers a digging depth of over 20 feet. Caterpillar, founded in 1925, sold thousands of E-series machines globally, and the E120B remains a common sight in private fleets and rural job sites.
Terminology Notes
Owners report that the E120B is a strong, reliable machine with minimal electronic complexity. Its mechanical systems are easy to service, and parts remain available through Caterpillar’s Classic Parts line. The excavator’s hydraulic response is smooth, and the swing torque is sufficient for most mid-size jobs. However, the machine lacks modern features like load-sensing hydraulics, electronic diagnostics, and fuel efficiency optimization.
In terms of durability, the E120B’s undercarriage is robust but prone to wear if neglected. Flat rollers, chipped pads, and worn shanks are common issues on older units. The swing gearbox and final drives should be inspected for metal shavings and fluid contamination before purchase.
Field Anecdotes and Practical Insight
In New Hampshire, a property owner purchased an E120B for $18,500 and used it for land clearing and drainage work. Despite minor issues like a failed oil pressure sensor and worn rollers, the machine performed well. He emphasized the importance of checking turntable seals and avoiding over-greasing, which can blow out seals and contaminate swing gear oil.
In Arkansas, a contractor noted that while the E120B is great for personal use, it’s less viable for commercial jobs unless paired with a transport solution. Without a CDL and a 20-ton trailer, moving the machine becomes costly. Clients rarely pay extra for mobilization, and leaving the machine on-site is often impractical.
Recommendations for Buyers
While the E120B may cost around $18,000–$22,000 in good condition, buyers should budget an additional $5,000–$10,000 for undercarriage work, hydraulic service, and minor repairs. Service manuals can be expensive, and some components may require fabrication or adaptation. However, with proper care, the machine can deliver thousands of productive hours.
Final Thoughts
The CAT E120B remains a viable excavator for personal use, landowners, and small contractors who value mechanical simplicity and rugged construction. It lacks modern efficiency and diagnostics but compensates with reliability and ease of repair. For those willing to inspect thoroughly and maintain proactively, the E120B offers solid performance at a reasonable price.
The Caterpillar E120B is a mid-size hydraulic excavator introduced in the late 1980s and produced through the early 1990s. Designed for general excavation, trenching, and light demolition, it features a mechanical fuel injection system, open-center hydraulics, and a robust steel frame. Powered by a Mitsubishi 6D16 diesel engine rated at approximately 110 horsepower, the E120B weighs around 27,000 pounds and offers a digging depth of over 20 feet. Caterpillar, founded in 1925, sold thousands of E-series machines globally, and the E120B remains a common sight in private fleets and rural job sites.
Terminology Notes
- Final Drive: The gear reduction system that powers the tracks, located at each side of the undercarriage.
- Swing Gearbox: A planetary gear system that rotates the upper structure.
- Shank: The welded base of a bucket tooth that holds the replaceable tip.
- Top Roller: An upper track roller that supports the track chain and maintains alignment.
Owners report that the E120B is a strong, reliable machine with minimal electronic complexity. Its mechanical systems are easy to service, and parts remain available through Caterpillar’s Classic Parts line. The excavator’s hydraulic response is smooth, and the swing torque is sufficient for most mid-size jobs. However, the machine lacks modern features like load-sensing hydraulics, electronic diagnostics, and fuel efficiency optimization.
In terms of durability, the E120B’s undercarriage is robust but prone to wear if neglected. Flat rollers, chipped pads, and worn shanks are common issues on older units. The swing gearbox and final drives should be inspected for metal shavings and fluid contamination before purchase.
Field Anecdotes and Practical Insight
In New Hampshire, a property owner purchased an E120B for $18,500 and used it for land clearing and drainage work. Despite minor issues like a failed oil pressure sensor and worn rollers, the machine performed well. He emphasized the importance of checking turntable seals and avoiding over-greasing, which can blow out seals and contaminate swing gear oil.
In Arkansas, a contractor noted that while the E120B is great for personal use, it’s less viable for commercial jobs unless paired with a transport solution. Without a CDL and a 20-ton trailer, moving the machine becomes costly. Clients rarely pay extra for mobilization, and leaving the machine on-site is often impractical.
Recommendations for Buyers
- Inspect Final Drive Fluids: Look for metal shavings or water contamination.
- Check Swing Gearbox Oil: Ensure proper level and absence of debris.
- Evaluate Undercarriage Wear: Flat rollers and chipped pads indicate deferred maintenance.
- Test Hydraulic Response: Smooth operation suggests healthy pumps and valves.
- Verify Parts Availability: Use CAT’s Classic Parts line for affordable replacements.
- Consider Transport Logistics: Factor in trailer, truck, and licensing costs.
While the E120B may cost around $18,000–$22,000 in good condition, buyers should budget an additional $5,000–$10,000 for undercarriage work, hydraulic service, and minor repairs. Service manuals can be expensive, and some components may require fabrication or adaptation. However, with proper care, the machine can deliver thousands of productive hours.
Final Thoughts
The CAT E120B remains a viable excavator for personal use, landowners, and small contractors who value mechanical simplicity and rugged construction. It lacks modern efficiency and diagnostics but compensates with reliability and ease of repair. For those willing to inspect thoroughly and maintain proactively, the E120B offers solid performance at a reasonable price.
