What Causes Bearing Failure in Your Final Drive?

Bearings play a key role in the performance of a final drive. If the bearing experiences wear and tear. It will generate vibrations that negatively impact the performance of your final drive.

The transmission efficiency also decreases. Bearing failure may even lead to failure of the entire system if not replaced soon enough.

But with proper maintenance measures and knowing the root causes of bearing failure. You can avoid bearing failure and make your bearings last longer.

This blog post will familiarize you with what causes bearing failure in your final drive. You will also get insights on preventing bearing failure in the excavator’s final drive. Sounds good? Read on to learn more!

Introduction: Bearing Failure

Bearing is a sliding contact, usually in the form of a shell or disc. It allows a shaft to drive against other elements that transmit torque. Bearing consists of balls, races, or shells.

The bearing function in the excavator’s final drive is to support the shaft and facilitate movement. Bearings also help prevent damage to pivot points, shafts, and gears by taking the load stress off them.

Causes of Bearing Failure

There are several causes of bearing failure. But some of the main causes that contribute to final drive bearing failure include:

  1. Poor Oil Level Maintenance
  2. Delay in Oil Replacement
  3. Contaminated Gear Oil
  4. Excessive Load
  5. Misalignment

Now we will discuss each cause one by one in detail:

1.   Poor Oil Level Maintenance

You must keep an eye on gear oil levels within your final drive. It is necessary to change it once every 100 operational hours.

If you observe a decrease in oil level, you must refill at an appropriate level. Avoid frequent refilling and overfilling as this will lead to leakage if you have damaged seals. Remember to refill with oil of the same category or type as per standards.

If the gear oil level drops below a certain point, it will result in low lubrication. You will be unable to operate your final drive effectively. The reason behind this is the grinding of needles, balls, or cylinders, especially regarding anti-frictional bearings.

When you talk about sleeve bearings, you will experience a metal-to-metal contact. The level of friction increases when a metal comes in direct contact with another metal. This will lead to rapid wear and tear. You can eventually experience complete damage.

2.   Delay in Oil Replacement

The final drive motor requires you to change the gear oil at least once a year. To do so properly, you first must completely drain any remaining oil. We recommend using pressurized air in doing so.

The age of gear oil finishes up over time. It loses its chemical composition and additive characteristics. The oil becomes more viscous when this occurs and develops a semi-solid form. In addition, you will also experience a foul smell which means now it is useless. These things also lead to speeding up wear and tear.

3.   Contaminated Gear Oil

Contamination of gear oil is common. The main contaminants which carry out the contamination process include sand, water, metal shavings, dust, and dirt. Metal shavings are a result of abrasive wear and tear.

The presence of shiny particles within your gear oil is the leading cause of damage. This occurs when a metal experiences direct contact with another metal. Lubrication is a process that helps you prevent any metal contact. This is particularly true for bearings.

Suppose the seals in your excavator’s final drive face a failure. They don’t only result in leakage of gear oil out from your final drive. But also allow foreign particles, including water and debris, inside your final drive.

Water is the key element that accelerates corrosion and renders your planetary hub failure. The abrasive particles among contaminants stick between the components. This leads to a reduction in efficiency and performance.

4.   Excessive Load

Excessive Load is a broad term for any load exceeding design limits. Excessive load is a root cause of failure in excavator final drive bearings. It results from too much weight on the gear (or races). Or excessive load application (e.g., torque) on an object for a specific period.

The load bearing strength of a bearing is proportional to the difference in pressure between the disc and housing rings. However, the excessive load on this bearing leads to very high temperature and pressure that can cause it to fail. If the load increases beyond the design limits, then this will lead to failure.

5.   Misalignment

Misalignment is an abnormality in the alignment of the bearing. It causes a clearance that leads to joint friction, wear, and internal scoring. Poor installation of these bearings results in misalignment, leading to premature wear and failure.

Non-professionalism and zero knowledge about final drive-bearing installation lead to these consequences. When this happens, it leads to early friction loss, increasing the chances of failure. This happens when the final drive assembly experiences higher loads in operation.

How to Prevent Failures of Bearing in Final Drive?

Everyone knows bearings have a certain life associated. After constant and frequent usage, they end up resulting in wear and tear if you are the one who is experiencing issues with replacing your bearings most often. Then it may be due to any one of the reasons mentioned above. You can practice the following measures to enjoy a longer life:

  • Determine the level of gear oil present in your excavator’s final drive after every 100 operational hours. If there is low oil, then refill up to the optimum level.
  • Replace the old oil with the new one of the same category and type at least once a year.
  • Please note to use the same oil as per the standards of the manufacturer
  • If there are any leaking seals, then replace them with the new one
  • Use accurate installation techniques to avoid excessive load and misalignment.

Following these measures, you will be able to experience a longer life with your Final Drive bearings. This will also increase their effectiveness and efficiency.


When your bearings face failure, it will lead to costly repairs and extensive downtime. You can avoid these issues by following in detail preventive measures. This blog has covered basic to in depth information on preventive measures. This will surely be going to help you in the long run.

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