EQUIPMENT FOCUS: Don’t get de-tracked

Sept. 7, 2010

Because the undercarriage on your compact excavator works as a system, wear is unavoidable.


Because the undercarriage on your compact excavator works as a system, wear is unavoidable.

“All of an undercarriage’s moving components—sprockets, idlers, chain and pads—are wear items,” said Jesus Santos, product specialist, Terex Construction Americas. “Because these components are costly to replace and time-consuming to install, you should protect your investment by taking the time to inspect and maintain your compact excavator daily. ”Did you know that the undercarriage is the most costly part of your excavator? It can make up almost 20% of your machine’s purchase price and nearly 50% of its maintenance cost. Such valuable components should never be neglected.”

1 Check track tension and sag to avoid excessive wear

One way to avoid premature or excessive wear of your undercarriage is to make sure that your compact excavator’s track chain is adjusted for correct tension. The components of your compact excavator’s undercarriage are designed to wear evenly. If some components wear more quickly than others, it can affect the productivity and wear of all the components.

“Loose tracks can de-track and can increase wear,” Santos said. “So be sure to check the track chain for proper tensioning every 10 to 15 hours of use, or at least every day. Tracks that are too tight can cause excessive roller and idler wear and can tear the tracks.”

Santos recommended the best way to inspect the tension of the track chain is to raise the machine up. In this raised position, the track should sag enough to leave about 10 to 15 mm of free space under the center track roller.

“For your excavator’s correct track inspection and tensioning procedures,” Santos said, “always refer to the operator’s manual for the manufacturer’s recommended guidelines.”

2 Keep the undercarriage clean and covered

Jobsite debris, like mud, snow and rocks, packed around the undercarriage also leads to faster component wear. Compact excavator manufacturers, including Terex, recommend that the undercarriage be inspected, cleaned and greased daily.

“At the end of each work day, knock away any debris that’s accumulated in the tracks,” Santos said. “Then, while the machine is still warm, wash it down to get rid of any remaining materials that could cause corrosion or contamination.”

The end-of-day wash-down process is a good time to remove embedded foreign objects from the tracks and to lubricate all moving parts.

“The daily wash-down is also an excellent time to look for any loose, worn, cracked, bent, broken or missing components,” Santos said. “Replace these items immediately.”

If your compact excavator is going to be parked for a period of time, particularly in the extreme heat, it is important to cover the tracks or to exercise the machine at least once a week. This prevents water and condensation from building up in the undercarriage and rotting the components.

3 Train every operator on the proper driving and digging techniques

Your excavator operators have more influence on the life and longevity of an undercarriage system than all of the manufacturer’s best efforts. Santos said, “The operation and upkeep of your compact excavator directly impacts your repair time and downtime costs.”

Santos recommends that each operator be taught the correct way to drive a compact excavator, understanding what he or she can do to keep it running in top form. For example, operating at higher speeds can cause more wear on the undercarriage, so drivers should apply the slowest possible operating speed for the job.

Also, Santos said, operators need to alternate their turning directions during the day—continuous turning to the same side can cause asymmetrical and accelerated wear. “And quick or sharp turns ought to be avoided entirely,” he said, “especially when operating in rocky conditions.”

Your operators should also learn to control track spinning when filling the bucket because unnecessary spinning also accelerates wear and causes cuts in the tracks. Operators also need to be cautious when driving over edges, curbs or other sharp angles to prevent breaks in the tracks.

“It is always best to use boards, beams or small ramps when driving on or off any angle,” Santos said.

Finally, your operators must learn to plan the machine’s movements with the terrain, not against it, to reduce wear.

“Working uphill adds stress to the rear of the machine, as working downhill shifts the stress to the front,” Santos said. “Balance the wear of the undercarriage’s components by alternating the work direction on the slope.” At the end of the day, usage conditions greatly influence the life and longevity of a compact excavator’s undercarriage. Proper care of this valuable investment will go a long way in reducing your maintenance costs.

Nine models

The Case Construction Equipment CX B Series excavators includes nine models, ranging in power from the 95-hp CX130B to the 532-hp CX800B. At the heart of the line are the 271-hp CX350B, the 362-hp CX470B and the 463-hp CX700B models, featuring excellent fuel efficiency, productivity, operator comfort and ease of maintenance. These excavators offer electronically controlled, common-rail 7.8-l Case engines.

Comfort and serviceability

Because the superstructure rotates entirely within the tracks without overhang, the Gehl 503Z zero-tail-swing excavators can be operated in tight confines, close to walls and other obstructions without compromising sight lines. Performance features include auxiliary hydraulics, heavy-duty booms, bucket options and canopy models. Gehl also resolves comfort and serviceability concerns by mounting the engine on the side of the unit and designing a tiltable cab. This results in larger cabs and easier service access.

Extended reach

A redesigned work group allows the new Bobcat 324 compact excavator to reach farther, dig deeper and dump higher. The excavator is a conventional-tail-swing unit in the 1.5-ton operating class. Its boom cylinder is attached to the top of the boom instead of the bottom, giving it more protection from damage while digging. It also features a lighter weight yet durable boom fabrication with cast pivot joints. 

Quiet comfort

Komatsu America Corp. has introduced the PC228USLC-8 hydraulic excavator. Komatsu’s latest tight-tail series builds on its previous model with hydraulic-system enhancements, improved operator control and comfort, increased lift capacity and stability and lower fuel consumption. With an operating weight of 53,195 lb to 54,405 lb, this machine is powered by a Komatsu SAA6D107E-1 engine. The electronically controlled high-pressure common-rail fuel injection system is EPA Tier III emissions certified and provides low-noise operation while remaining extremely fuel efficient.


The 70-ton Volvo EC700C excavator has a powerful 430-hp Volvo Tier III/Stage IIIA-compliant engine with V-ACT (Volvo Advanced Combustion Technology) offering high torque at low revs, leading to ultra-efficient fuel consumption. An advanced hydraulic system, well matched for smooth, responsive digging and lifting, features high breakout force, crowding force and slew speed. It has a Volvo Care Cab with operator protective structure, more space, increased safety, better visibility and reduced whole- body vibration.

Bigger and better

Takeuchi announces the addition of the TB228 excavator to its lineup of products. The Takeuchi TB228 compact excavator is a 24.3-hp machine with an operating weight of just over 6,000 lb, maximum digging depth of 9 ft 5 in., maximum bucket digging force of 6,471 lb and a traction force of 6,334 lb. It features a EPA Tier IV-compliant engine, two-speed travel with automatic shift-down, choice of rubber or steel tracks and electrohydraulic push-button control of auxiliary hydraulics.

Comfortable and confident

The new Cat 314D CR and 314D LCR (long undercarriage) hydraulic excavators are compact-radius models that build on the valued attributes of their C-Series predecessors with a new fuel-efficient Cat C4.2 ACERT engine, more hydraulic power, expanded work-tool versatility, spacious operator station and intermediate-length stick. These 90-hp, 14-metric-ton machines have the features to cut operating costs, boost production, increase machine potential and keep operators comfortable and confident.

The big one

Doosan introduces its largest crawler excavator, the DX700LC. Powered by a six-cylinder, 463-hp turbocharged Isuzu diesel engine, it has an operating weight of 158,953 lb with standard boom and arm, 35.4-in. double grouser shoes and 4.32-cu-yd bucket. Bucket breakout force is 78,485 lb with the standard bucket, while arm breakout force is 78,044 lb. Maximum digging reach is 40 ft 10 in. at ground level, and maximum digging depth is 25 ft 4 in.

Built for consistency

The zero-tail-swing, 72-hp Terex TC75 compact crawler excavator is able to handle 3.2- to 13.2-cu-ft bucket capacities and is ideal for using a hydraulic hammer. The 92-in.-wide dozer blade is independently controlled from the track drive for uninterrupted operation. And, with a flip of a switch, operators can change from ISO to SAE controls. This unit weighs 17,420 lb and achieves a maximum dig depth of 14 ft 7 in. and a maximum reach of 24 ft 5 in.

Fewer machines, faster service

The XL 4300 III Gradall excavator can lift and move heavy loads off the two sides as well as the front and rear of the chassis without the use of outriggers. Exceptionally stable with front-axle oscillation locks, this excavator, at 43,000 lb, is equipped with a telescoping, tilting boom and a host of attachments. Because the entire boom tilts, the XL 4300 III does not lose any boom-end power on high-productivity jobs requiring mass excavation, trenching, spreading rip-rap, demolition and pavement removal.

Power in confined space

Kubota introduces the U55, its largest model in the U-Series of compact excavators. The new 5-ton tight-tail-swing compact excavator is designed to provide outstanding power while working in tight jobsites. It features a medium-length arm that enhances arm-crowd force, a wide doorway and plenty of operator space. With only 2.5 in. of tail-swing overhang, the U55 is powerful, yet compact enough to operate efficiently and carefully in narrow work spaces.

Smooth power, fuel savings

John Deere is offering two new mid-size hydraulic excavators in the 12- to 13.5-metric-ton range: the 120D and 135D. The 120D is designed for jobs such as excavating basements or placing pipe and transports easily. The 135D is a reduced-tail-swing machine capable of maximum production in confined areas and works within a single lane of traffic. A short counterweight allows it to dig near buildings and obstructions. Tungsten-carbide-coated surfaces and oil-impregnated boom, arm and bucket bushings deliver long-term durability.

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