You’ve been having issues with your final drive, and you’ve started to take it apart to track down the problem. You’ve cleaned the bearings up, but how can you tell if it’s time to replace them? In this Shop Talk Blog post, we are going to delve into the signs that your bearings need to be replaced.

Importance of Bearings in a Final Drive

Bearings are another one of the vital components that make up your final drive motor. They serve several different purposes, such as keeping gears and shafts positioned correctly, minimizing friction and heat generation, and keeping parts in alignment. As they perform these critical tasks, they are carrying very high loads at very high temperatures. Signs of their imminent failure include vibration, noise, and overheating. When they experience a catastrophic failure, they can quickly total your final drive motor. In this image, you can find a disturbing example of what can happen when a bearing goes bad.

What To Look For

When you inspect your bearings, begin by looking for obvious signs of damage. These include:

• Dented seals
• Damaged or broken separators
• Cracks in the race
• Damaged or broken balls/rollers
• Flaking, scratched, or pitted races/balls/rollers
• Wear tracks on the outer race

If you see any of these signs, it’s time to replace that bearing.  Also, if the balls/rollers are no longer inside the bearing, that's another definite sign that it's time to replace the bearing.

Next, look for signs that the bearing has overheated. When bearings overheat, it can affect the heat treatment that is critical to effective bearing performance. What you need to keep an eye out for are areas that have a bluish-black or brownish-black hue. If you see this type of discoloration, then the bearing needs to be replaced.

Check the seals carefully, too. If the seals are worn or damaged, then they can allow moisture and contaminants to enter the bearing. Seals that are in poor condition will significantly shorten bearing life, so damaged or worn seals are a sign that a bearing needs to be replaced.

Next, lightly lubricate the bearing and slowly turn the outer race (slowly, don’t spin it) and watch for click or sticking. For a tapered roller bearing or thrust bearing, place it on a clean surface and apply light pressure with your hand and gently to try turn it. If you notice clicking or sticking, try cleaning the bearing again. If it is still clicking or sticking, then it needs to be replaced.

When to Replace a Bearing

Bearings with low service hours that don’t show any of the signs of damage  discussed do not need to be replaced. Notice we said “low service hours”: if your bearing has a lot of service hours on it, we strongly recommend replacing that bearing. Here’s why: it has a limited life span left, and when a bearing fails it can cause damage that is both extensive and expensive. That's why we recommend replacing bearings with high service hours as a precaution. Not all damage is visible to the naked eye, and there is a high probability of this kind of “invisible damage” being present in a high service hour bearing.

Conclusion

Final drive bearings are a critical component in your propel motor. If you have any doubt as to the condition of a bearing, your wisest choice would be to replace it -- especially if it has high service hours.

Texas Final Drive is your partner in providing new or remanufactured final drive hydraulic motors from a single mini-excavator to a fleet of heavy equipment. Call today so we can find the right final drive or hydraulic component for you, or check out our online store to find your O.E.M. manufacturer brand motor now.