11-12-2025, 01:34 PM
The Legacy of the Hitachi EX120 Series
The Hitachi EX120-3 excavator belongs to a lineage of compact hydraulic excavators that gained popularity in the 1990s and early 2000s. Hitachi Construction Machinery, founded in 1970 as a division of Hitachi Ltd., quickly became a global leader in earthmoving equipment. The EX120 series was designed for mid-range excavation tasks, offering a balance between power, maneuverability, and fuel efficiency. By the time the EX120-3 was released, Hitachi had already sold tens of thousands of units worldwide, particularly in North America and Southeast Asia, where infrastructure development was booming.
The EX120-3 features a 4-cylinder Isuzu diesel engine, typically the BB-4BG1T model, producing around 90 horsepower. With an operating weight of approximately 27,000 pounds and a digging depth of nearly 20 feet, it’s well-suited for trenching, site prep, and utility work. Its hydraulic system is known for reliability, and many units remain in service decades after their release.
Key Inspection Points Before Purchase
When evaluating a used EX120-3, several components require close attention:
A common question among buyers is whether a machine equipped with a hydraulic thumb can also run a hydraulic hammer. The answer is yes—with modifications. The thumb and hammer both require auxiliary hydraulic flow, but their return paths differ.
One operator purchased an EX120-3 for $32,000 after inspecting it out of state. The machine had 4,600 hours and was well-maintained, though the coupler had minor slack. This was resolved with shimming and welding. The bucket had a broken ear, which contributed to looseness but was manageable.
Upon delivery, the operator planned to switch the control pattern from CAT-style to Deere-style, reflecting personal preference. While some experts caution against changing patterns due to potential mismatches in relief valve settings or hose lengths, others note that switching pilot lines is a straightforward task if done carefully.
Advice for Prospective Buyers
The Hitachi EX120-3 remains a dependable choice for contractors seeking a mid-sized excavator with proven durability. With proper inspection and minor hydraulic adjustments, it can accommodate a range of attachments including thumbs and hammers. Its legacy in the construction industry is built on reliability, and with thousands still in operation, it continues to be a smart investment for earthmoving professionals.
The Hitachi EX120-3 excavator belongs to a lineage of compact hydraulic excavators that gained popularity in the 1990s and early 2000s. Hitachi Construction Machinery, founded in 1970 as a division of Hitachi Ltd., quickly became a global leader in earthmoving equipment. The EX120 series was designed for mid-range excavation tasks, offering a balance between power, maneuverability, and fuel efficiency. By the time the EX120-3 was released, Hitachi had already sold tens of thousands of units worldwide, particularly in North America and Southeast Asia, where infrastructure development was booming.
The EX120-3 features a 4-cylinder Isuzu diesel engine, typically the BB-4BG1T model, producing around 90 horsepower. With an operating weight of approximately 27,000 pounds and a digging depth of nearly 20 feet, it’s well-suited for trenching, site prep, and utility work. Its hydraulic system is known for reliability, and many units remain in service decades after their release.
Key Inspection Points Before Purchase
When evaluating a used EX120-3, several components require close attention:
- Pins and Bushings These are wear points in the boom, stick, and bucket linkage. Excessive play indicates long-term wear and may require replacement or line boring.
- Hydraulic System Look for leaks, smooth operation, and consistent pressure. The thumb attachment, if present, should operate without hesitation or jerky movements.
- Swing Motor and Bearing Check for unusual noises or resistance when rotating the upper structure. A failing swing bearing can be costly to replace.
- Undercarriage Inspect track tension, roller wear, and sprocket condition. These components often reflect the machine’s overall usage history.
- Control Pattern Configuration The EX120-3 may be set up with excavator-style controls (ISO) or backhoe-style (SAE). Without a pattern changer, switching requires rerouting pilot lines—typically four hoses. While not technically difficult, it demands familiarity with hydraulic schematics and careful labeling.
A common question among buyers is whether a machine equipped with a hydraulic thumb can also run a hydraulic hammer. The answer is yes—with modifications. The thumb and hammer both require auxiliary hydraulic flow, but their return paths differ.
- Hammer Return Line Requirements A hydraulic hammer must return oil directly to the tank, bypassing the control valve to prevent backpressure. This can be achieved by installing a T-fitting on the return line and using gate valves to switch between thumb and hammer modes.
- Installation Kit Many operators use a hard and soft line kit bolted to the boom, which includes fittings, valves, and a dedicated return hose. This setup allows quick switching between attachments without compromising hydraulic integrity.
- Pilot Lines: Small-diameter hydraulic hoses that control the main valves via low-pressure signals.
- Gate Valve: A valve that opens or closes flow in a hydraulic line, often used to redirect oil between attachments.
- Control Pattern: The configuration of joystick movements that control boom, stick, bucket, and swing functions.
One operator purchased an EX120-3 for $32,000 after inspecting it out of state. The machine had 4,600 hours and was well-maintained, though the coupler had minor slack. This was resolved with shimming and welding. The bucket had a broken ear, which contributed to looseness but was manageable.
Upon delivery, the operator planned to switch the control pattern from CAT-style to Deere-style, reflecting personal preference. While some experts caution against changing patterns due to potential mismatches in relief valve settings or hose lengths, others note that switching pilot lines is a straightforward task if done carefully.
Advice for Prospective Buyers
- Budget for Transport Moving a 27,000-pound machine across states can cost between $2,000 and $5,000 depending on distance and permits.
- Check for Missing Decals While cosmetic, missing decals may indicate repainting or prior damage.
- Test All Functions Before purchase, operate the boom, stick, bucket, swing, and travel functions. Listen for hydraulic whine or hesitation.
- Document Modifications If the machine has been retrofitted with a thumb or hammer circuit, ensure documentation exists for future maintenance.
The Hitachi EX120-3 remains a dependable choice for contractors seeking a mid-sized excavator with proven durability. With proper inspection and minor hydraulic adjustments, it can accommodate a range of attachments including thumbs and hammers. Its legacy in the construction industry is built on reliability, and with thousands still in operation, it continues to be a smart investment for earthmoving professionals.
