Keys to compact excavator maintenance and longevity

Regardless of its size, a compact excavator requires the same maintenance and care as its larger counterparts. With all the same components of standard-sized excavators, a mini ex demands thorough maintenance to provide the dependable performance required on the jobsite and achieve the desired service life. Giving proper attention to routine maintenance — what you might call “sweating the small stuff” — can yield big results in keeping your compact excavator productive on the job.

Track Tension

A frequently overlooked service point on compact excavators is track tension. Most mini excavators have rubber tracks, which must be kept properly adjusted to maximize longevity and minimize wear on the track and its components. A track running loose will accelerate wear, cause unnecessary downtime and halt production when the reinstallation of a new track is needed. On the other hand, a track running too tight will cause the rubber material to tear and will greatly increase wear on the other track system components, including traction motors, sprockets and front idlers. Operators should always refer to the operator’s manual and check track sag measurements on a regular basis to ensure the track tension is correct.


Grease is the lifeblood of all pins and bushings. As a general rule, operators should grease all pins and bushings daily. The operator’s manual will identify each grease point and provide recommendations for quantity and grade of grease. If multiple operators are using a single machine, you can mark less obvious grease points, such as the turntable bearing, with orange marking paint around the grease nipple to remind all users to perform this task. As with undergreasing, overgreasing can also be problematic. One to three shots of grease is typically plenty to do the job. Using more wastes money, presents a potential environmental hazard and can cause a considerable mess.

The Gearbox

The propel drive gearbox, one of the most vital components of a machine’s performance, is often neglected when it comes to servicing. Because gearboxes are often covered in mud, with the fill and drain plugs not visible, operators and service personnel rarely notice them. However, gearboxes require an oil change at approximately 1,000-hour intervals, depending on the manufacturer. Propel drive gearboxes from some manufacturers may fail as early as 1,500 to 3,000 hours. Gearboxes for compact excavators may be small, but they are still expensive to manufacture because they have the same internal parts as their larger cousins. You can change the gearbox oil quickly in most cases because the typical gearbox oil capacity is a quart or less, so this maintenance step is a small investment that will pay off in the future.

Hydraulic Oil

Recordkeeping may be  the most tedious and  time-consuming of all tasks, but keeping service records and invoices for oil, filters and repairs up to date can provide invaluable information in the future.

Recordkeeping may be
the most tedious and
time-consuming of all tasks, but keeping service records and invoices for oil, filters and repairs up to date can provide invaluable information in the future.

Countless machines have never had a hydraulic oil change. Hydraulic oil can be misleading because, although it may look clean (just like engine oil), it breaks down and loses its viscosity and its ability to hold contaminants in suspension. Clean oil helps protect all moving parts in the system. Hydraulic systems are designed for precise tolerances, and most hydraulic failures can be traced back to contaminated
hydraulic oil or even the wrong type of hydraulic oil.

One of the many important functions of hydraulic oil is that it absorbs moisture in the system and keeps it away from the hydraulic components. You may not think that rust can be a problem in a sealed hydraulic system that is always full of oil, but it is. Service personnel have disassembled failed hydraulic pumps and hydraulic system components and have found rust on the rotating group and in the housings.
Don’t make the mistake of thinking just because hydraulic oil looks good that it is. By the time hydraulic oil becomes cloudy, it is far beyond the point when it should have been changed and has lost much of its ability to properly protect the components in the hydraulic system. Most equipment manufacturers suggest a hydraulic oil change interval in the 2,000- to 4,000-hour range, but every machine is different. Your operator’s manual will provide a specific servicing timetable and oil requirements.

Tier 4 Engine Maintenance

The recent addition of Tier 4 emissions control technology has had minimal impact on operations or maintenance. Most compact equipment now use engines that achieve mandated emissions levels via cooled exhaust gas recirculation, or CEGR, technology. CEGR recirculates exhaust back into the engine to reduce NOx formation and uses a diesel particulate filter (DPF) to capture pollutants. The DPF is usually designed to last for thousands of hours and is readily accessible, so replacing it is easy, even on machines with heavy work schedules that require more frequent changes. Periodic regeneration may be completed passively or manually to burn off accumulated particulates from the DPF (consult your owner’s manual for intervals and recommended procedures). Additionally, manufacturers recommend the use of higher grade oil and ultra-low-sulfur diesel fuel in machines with CEGR engines.

You may encounter some compact equipment with engines that use selective catalytic reduction, or SCR, to meet Tier 4 emissions limits. SCR reduces particulate matter in the combustion chamber and treats exhaust gases with diesel exhaust fluid (DEF) to eliminate pollutants. Most SCR systems require regular filling of the DEF tank, which can be done as part of normal maintenance when checking fluid levels or when refueling. The bottom line in managing maintenance needs for Tier 4-certified equipment is following practices that help achieve lower total cost of ownership, better performance and improved productivity.


Recordkeeping may be the most tedious and time-consuming of all tasks, but keeping service records and invoices for oil, filters and repairs up to date can provide invaluable information in the future when evaluating the service life of your machine. All equipment will come to the end of its service life eventually, and if you keep accurate information, you will have a baseline to evaluate the performance of the machine and make an informed decision about whether to buy the same manufacturer’s product again or make a switch to a different brand.

Proper service records are also helpful when working with your dealer if an issue with your machine arises. Accurate records will prove to both your dealer and the manufacturer that you care about your equipment and that you are servicing the machine as required. This principle can be crucial when dealing with warranty claims and is necessary whether you have an entire fleet of mini excavators or just a single machine. Good service records also can help boost resale value.

Next time you service the engine oil and fuel filter on your mini excavator, check your operator’s manual, take a little extra time and money to service your machine properly and always document the service. These maintenance habits are the most cost-effective ways to ensure minimal downtime in the future. In the long run, you and your bottom line will be glad you did.

Lee Shirey is a training team leader for Hyundai Construction Equipment Americas.

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