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The Critical Role of Pins and Bushings in Heavy Equipment (And How to Prolong Their Lifespan)
The Critical Role of Pins and Bushings in Heavy Equipment (And How to Prolong Their Lifespan)
Reading time: 6 min
Pins and bushings play an important role in the movement and functionality of nearly every type of heavy construction equipment. In this guide, we’ll delve into the basics of pins and bushings, including their maintenance requirements.
The Basics of Pins and Bushings in Construction Equipment
Pins and bushings enable a machine’s tracks to rotate smoothly about the undercarriage, making them indispensable to a machine’s performance.
Bushings, which are hollow and cylinder-shaped, form a sleeve that slots into the holes on one end of a track link. Pins are inserted through the holes of the track links and through the bushing, connecting two track links.
As a machine’s tracks rotate about the undercarriage, the pins turn inside of the bushings, allowing the track links to pivot at the joints formed by the pins and bushings.
The inside of the bushings are lubricated, helping reduce friction and prevent excessive wear to the pins/bushings as the pins rotate. Some pins/bushings are self-lubricating, constantly drawing oil from a small oil reservoir inside of the pins.
Types of Equipment That Rely on Pins and Bushings
Pins and bushings can be found in nearly all tracked heavy equipment as they are necessary to facilitate the movement of the tracks. While pins and bushings are primarily found in the undercarriage, they are commonly used to form joints between other components, as well.
For example, an excavator’s bucket is commonly secured to the dipper using pins and bushings. This allows the bucket to pivot about the dipper with low friction, facilitating smooth movement and decreasing wear to the machine’s structural components.
Popular uses for pins and bushings in heavy equipment include:
- Excavators: Pins and bushings are used to connect the boom and arm, to connect the bucket to the arm and to facilitate the movement of the tracks.
- Dozers: Pins and bushings are essential for connecting the blade to the dozer frame and for connecting the links of the track chain in tracked dozers.
- Backhoes: Pins and bushings connect the backhoe arm to the rear of the machine and enable the smooth tilting of the bucket and other attachments.
- Skid Steers: Pins and bushings are used in the connections between the arms and the frame, as well as in various attachments such as buckets and forks.
In nearly all tracked machines, you’ll find pins and bushings at work in the undercarriage. Pins and bushings are the components responsible for connecting the links of a machine’s track chain, enabling the smooth rotation of the tracks.
While pins and bushings are technically two distinct components, they are almost always discussed as a pair. This is because the two components rely on each other to perform their function.
In simple terms, pins and bushings are used to form a joint between the links of a machine's track chain. Like the rods that connect the links of a bicycle chain, pins and bushings slot into holes in a track’s links, binding the links together and enabling the fluid movement of the track.
A bushing is a sleeve-like, hollow cylinder made from steel. Pins, which slot into the bushings, are steel rods, which rotate inside the bushings, forming a joint.
Factors Affecting the Lifespan of Pins and Bushings
While pins and bushings are designed to withstand constant friction and mechanical stress, there are certain factors that may negatively impact their lifespan.
Load and Stress
Heavy loads and high stress during operation can accelerate wear on pins and bushings. Regularly operating equipment at or near its specified capacity can result in the need to replace the pins and bushings more frequently.
Lubrication
Inadequate lubrication is a common cause of wear and friction. Insufficient or irregular lubrication can lead to increased friction as the pins rotate inside of the bushings, causing accelerated wear.
Dirt and Contaminants
Exposure to dirt, sand and other harsh contaminants can compromise the integrity of pins and bushings. Abrasive particles, such as silica, can infiltrate the joint, leading to increased wear and friction.
Material Quality
The quality of materials used in manufacturing pins and bushings is critical. High-quality, durable materials can withstand heavy loads and resist wear better than inferior or low-quality materials.
Maintenance Tips for Pins and Bushings
Maintaining your machine’s pins and bushings is crucial for its longevity and performance. Here are some maintenance best practices for these components.
- Inspect pins and bushings regularly
- Follow manufacturer guidelines for lubrication intervals
- Use the correct type of lubricant for the operating conditions
- Keep your machine clean and clear of debris, especially in the undercarriage
- Ensure the pins and bushings are aligned properly during installation
- Regularly measure the wear to the pins and bushings and follow manufacturer guidelines for replacement or turning
- Operate the machine within its specified load capacity
The Importance of Lubrication
Lubrication plays a pivotal role in sustaining the performance and durability of pins and bushings in heavy equipment. By reducing friction between the pins and the interior side of the bushings, lubrication safeguards against wear.
Additionally, the protective film created by lubricants serves as a barrier against moisture and corrosive elements. Proper lubrication can contribute to proper load distribution, ensuring even stress across surfaces.
The two main lubricants used in pins and bushings are grease and oil. The frequency of lubrication depends on factors such as the operating environment, usage and the lubrication requirements of your particular pins and bushings.
For best results, lubricate your machine’s pins and bushings according to the guidelines given in the machine’s service manual.
Replacing vs Turning Pins and Bushings
Replacing your machine’s pins and bushings on time is crucial to prevent larger mechanical issues. As these components undergo regular wear during operation, failing to replace them on time could lead to misalignment and the accelerated deterioration of other components of the undercarriage.
Sometimes, you may choose to turn your machine’s pins and bushings rather than replace them. This is a useful approach if the wear to your machine’s pins and bushings is one-sided, as turning them will allow wear to occur on the unaffected side. For more information about this, check out our guide on turning pins and bushings.
Final thoughts
Caring for your machine’s pins and bushings represents a key aspect of undercarriage maintenance. These components are critical to reducing wear and friction in your machine. Maintaining them properly is a worthwhile investment of time and resources.
If you’re looking for OEM and aftermarket pins and bushings for your heavy equipment, then check out the EquipmentShare Shop. Our extensive online catalog makes it easy and convenient to find the part you need to get back on track. Don’t see exactly what you’re looking for? Reach out to our dedicated parts experts and get personalized assistance.
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