Blog Single

Undercarriage is the base of Kobelco crawler crane that supports the entire weight of the equipment and also gives traction and stability on different work sites. Among the components of the undercarriage, track shoes have the maximum exposure to the surface of the earth, as they are directly exposed to the ground surface, which leads to wear and tear because of abrasive particles and rough surface of the ground.

Replacement of Kobelco track shoes that have been worn out or damaged is an important safety step that needs proper attention and care regarding the techniques and guidelines given by the manufacturer of the equipment. This article combines data from various sources, including Kobelco manuals.

When to Replace Kobelco Track Shoes

Prior to any replacement of track shoes, the operator should know when track shoe replacement is needed. Some of these conditions include:

Lug Height Wear: In cases where the lug height (A) goes below 5 mm (0.2 inch), there is a significant loss in drawbar pull because of reduced traction and control.

Exposed Steel Cord: In cases where the lugs are worn out and the steel cord is exposed on two or more links, it is time for replacement. In cases where there is a breakage of more than half of one steel cord, the shoe needs to be replaced.

Cracking: In cases where there are cracks of 60 mm (2.4 inches) or more in length between lugs, it is necessary to fix or replace the track shoe. Shorter cracks that expose inner steel cords require immediate replacement of track shoes.

Core Metal Wearout: In some cases, despite no damage to the lug side of the track shoes, the core metal side may be damaged by coming into contact with the rollers, idlers, or sprockets. This requires replacing the track shoes in case of any core metal wearout.

Safety Precautions Before Starting

Machine Lifting: Machine has to be lifted to change the rubber track shoes. Safety struts should properly hold the lower frame so that there is no accidental fall while changing them.

Grease Cylinder Pressure Caution: Grease cylinders have high-pressure grease loaded in them. Nipple of the grease cylinder should be loosened slowly by about one turn only while keeping your face and body away from it. Nipple may shoot out because of the pressure inside the cylinder. If opened quickly, grease may fly off.

Thorough Cleaning: Sand, soil, and other debris from around the tracks should be cleaned before carrying out any operation.

Essential Tools and Replacement Parts

Prior to undertaking replacement, operators are expected to prepare the following :

Track Shoe Bolts: High strength bolts usually made of alloy steel and have a high grade of hardness (Grade 10.9 or 12.9). Examples of common bolts used for large excavators are the M27 x 2.0.

Torque Wrench: Important tool needed for obtaining proper specification of bolt fastening. The Kobelco workshop manuals state that torque wrench settings must be strictly adhered to.

Safety Equipment: Consisting of safety struts, lifting equipment, and personal protective equipment.

Replacement Track Shoes: Available in rubber track shoes for compact excavators and steel track shoes for large excavators. Operators are encouraged to check their compatibility with their particular Kobelco model.

Step-by-Step Track Shoe Replacement Procedure

Preparation and Positioning

1. Position the Rubber Joint: Move the rubber joint (marked with an “M”) of the track shoe to the upper center between the axles.
2. Swing and Secure: Swing the machine 90 degrees, place the bucket on the ground, and retract the boom cylinder to raise the track shoe requiring replacement. Support the lower frame with safety struts.
3. Release Track Tension: Locate the grease nipple on the track spring grease cylinder. Loosen the nipple gradually within one full turn to release high-pressure grease. Ensure all grease is completely drained before proceeding

Removing the Worn Track Shoe

1. Turn the Sprocket: After confirming grease drainage, turn the sprocket to position the track shoe for removal.
2. Remove Bolts: Extract the track shoe bolts using appropriate tools. Note that track shoe bolts are typically high-strength fasteners requiring care to avoid damage.
3. Detach the Shoe: Remove the worn track shoe from the track link assembly. If the shoe does not loosen easily, contact an authorized Kobelco dealer rather than forcing removal 

Installation Procedure

1. Inspect Components: Before installing new track shoes, carefully inspect the shoe body, pinholes, and wear layer. Check for proper alignment of bolt holes.
2. Position New Shoe: Align the new track shoe with the track link assembly, ensuring proper orientation of bolt holes.
3. Install Bolts: Insert track shoe bolts and tighten to manufacturer specifications. Kobelco manuals provide specific torque values for different models. For SK200-8 and SK250-8 series, track shoe bolt tightening torque requires precise attention.
4. Adjust Track Tension: After installation, adjust track shoe tension according to operating conditions. Proper tension “A” for rubber track shoes ranges from 70 to 80 mm, while iron shoes require 120 to 135 mm.

Conclusion

Kobelco track shoe replacement is a critical maintenance task that will affect the performance, safety, and durability of the machine. With the use of manufacturer recommendations in terms of safety practices, proper tensioning, and the right bolt torque, you can be assured of efficient undercarriage operations even in different work environments.

Proper inspection of lug height, steel cord integrity, and core metal condition will help identify any wear before breakdowns occur, thus reducing any downtime. It doesn’t matter whether you perform the track shoe replacement on your own or through authorized dealers; the track shoe condition will still be critical.