Common Problems With Track Idler of Excavator: Detailed Analysis and Maintenance Tips

Excavators and bulldozers are common construction machinery, and track idlers are key components of these machines. The track idler is part of the track system, which is used to guide the normal operation of the track, maintain the tension of the track and the stable contact with the ground.

The core difference between the track idler of the excavator and the track idler of the bulldozer

Although both excavators and bulldozers are equipped with track idlers, there are some significant differences between the track idlers of these two machines:

Differences in structural design and force environment

Excavator track idler:

• Usually a single flange or double flange structure is adopted, which needs to withstand the lateral impact caused by frequent turning and climbing.
• Because the excavator needs to rotate at multiple angles during operation, the meshing frequency of the track idler and the track is higher, and asymmetric wear is prone to occur.

Bulldozer idler:

• Most of them are designed as a wide double flange structure, emphasizing the stability of linear bulldozing operations, and mainly bear longitudinal pressure.
• The track idler material of the bulldozer focuses more on compressive strength, while the track idler of the excavator needs more impact toughness.

Functional differences

• The track idler of the excavator is mainly used to ensure the smooth operation of the crawler and help guide the crawler around the curve. Since the excavator needs to operate on a variety of complex terrains, the track idler is usually designed to be more delicate and complex in structure.
• The track idler of the bulldozer is usually simpler, and its main function is to maintain the tension of the crawler to ensure that the crawler can withstand greater pressure when the bulldozer is operating. Since the bulldozer works on relatively flat ground, the track idler of the bulldozer is mostly a single strong support.

Material and process requirements

• ZG35Mn or 42CrMo alloy steel is commonly used for the track idler of the excavator, and the wear resistance is improved by quenching and tempering + surface quenching.
• The track idler of the bulldozer tends to be cast with high carbon steel, and the surface is carburized to cope with sand and gravel wear.

Differences in wear caused by working conditions

• Excavators are often found in complex terrain (such as mines and construction sites), and track idlers are susceptible to the intrusion of gravel and mud, resulting in seal failure.
• Bulldozers mostly operate on flat ground, and are mainly faced with sand wear and grease degradation caused by high temperature.

Possible problems and causes of track idlers

Although track idlers play a vital role in normal operation, they also have some common problems due to frequent use and environmental factors. Here are some common problems and their possible causes:

Wear too fast

• Phenomenon: Uneven thickness of wheel rim, pits or peeling on tooth surface, resulting in unstable track operation.
• Cause analysis:
  • Low track tension leads to slippage and friction.
  • Hard particles (such as gravel) on the working ground are embedded between the track and the track idler, forming abrasive wear.
  • Failure to adjust the track offset in time causes unilateral force overload.

Track idler tilt or deformation

• Phenomenon: Tilt or deformation occurs.
• Cause analysis:
  • Usually due to long-term lack of maintenance, internal parts are worn or damaged, or uneven load on the track causes uneven force on the track idler.

Bearing stuck or abnormal sound

• Phenomenon: Increased rotation resistance and metal friction sound.
• Cause:
  • Aging of the seal ring leads to muddy water infiltration and grease contamination.
  • Long-term overload operation causes pitting of the bearing raceway.

Wheel body fracture

• Phenomenon: Rim cracks and hub fractures.
• Cause:
  • Material defects (such as casting pores, improper heat treatment).
  • Overload impact (such as falling from a height or hitting a hard object).

Track falls off or is unstable

• Phenomenon: Track falls off or runs unsteadily.
• Cause:
  • This may be caused by severe wear or improper installation of the track idler, which makes the track unable to run stably, thus affecting work efficiency.

How to deal with problems with the track idler?

Once a problem with the track idler is found, it is very important to deal with it in time to avoid the problem from getting worse. Here are some common problems:

Wear repair technology

• Mild wear: Use wear-resistant welding rods (such as D256) to repair the wheel rim by surfacing welding, and restore the size after processing.
• Severe wear: Replace the track idler to match the equipment model (such as Komatsu PC200-8 requires a special track idler).

Bearing maintenance process

• Remove the track idler and remove the old grease.
• Check the bearing raceway. If pitting occurs, replace the SKF/NSK brand bearing.
• Fill with lithium-based grease (NLGI grade 2), and replace the seal with a double-lip skeleton oil seal.

Emergency treatment of wheel body fracture

• Stop the operation immediately to avoid debris damaging the track.
• Contact GFM technical support and provide the equipment serial number for quick transfer.

How to perform daily maintenance to avoid problems with the track idler?

In order to avoid problems with the track idler, daily maintenance is particularly important. Here are some suggestions:

Regular inspection

Regularly check the track idler and other related components, such as bearings, track tension, etc., to ensure that they are in normal working condition.

Keep lubricated

Use appropriate lubricants to regularly refuel the track idler bearings and other components to reduce friction loss and extend service life.

Avoid overload operation

When using an excavator or bulldozer, try to avoid overloading, especially on uneven or hard ground, to prevent the track idler from being damaged due to excessive load.

Cleaning and maintenance

After each operation, clean the mud and sand on the machine to prevent debris from entering the track idler system and causing friction and wear.

Check track tension

Keep the track tension within the recommended range to avoid excessive or insufficient tension, which will cause excessive wear of the track idler.

The track idler is an indispensable component in the track system of excavators and bulldozers. Regular inspections, timely handling of problems, and scientific daily maintenance are the key to ensuring the normal operation of the track idler and extending its service life. By understanding the causes of common problems and how to deal with them, you can effectively reduce equipment failures, improve work efficiency, and reduce maintenance costs.