Industrial lubricant application and maintenance FAQ

Typically, equipment builders’ manuals include a recommendation on oil change intervals and other related maintenance schedules. We also recommend using tools such as Mobil Serv℠ Lubricant Analysis to determine whether in-service oil requires replacement. Read more about our Mobil Serv Lubricant Analysis program or contact your distributor for more information.

In general, the recommended shelf life for oils and greases is five years, when stored properly in the original sealed containers. However, a variety of factors can impact recommended shelf life. You can find a detailed shelf life explanation here. 

Mixing different greases, even those with similar thickener types, can sometimes lead to ineffective lubrication resulting in damage of the lubricated components. If not spotted soon enough this may lead to equipment failure.

For specific information please consult the Technical Topic titled "Grease compatibility."

Many rolling element bearings require relubrication of small quantities of grease between grease flushing intervals. This is best done with a low-pressure grease gun. If seals are in good condition, the quantity of grease needed may be small and infrequent.

1. Check the amount of grease in the bearing – remove fitting or grease plug to allow excess grease to come out.
2. Check bearings and seals for excess leakage.
3. Apply a few “shots” of grease at a time.

Ahead of applying a new grease, thoroughly clean – or flush out – the previous grease from the bearing. This avoids compatibility issues and helps ensure that the new grease can perform at an optimum level.

If this cannot be carried out, mitigating actions should focus on minimizing the amount of the displaced grease remaining in the application, such as by increasing relubrication frequency to facilitate a purge of old grease in a timely manner.

Where bearings are subject to contamination, more frequent relubrication may be necessary.

Contamination will lead to unusual operation such as hot, noisy, vibrating or leaking bearings. Be sure to spot, report and act on those.

Be sure to clean up all excess grease and dirt from the bearing and surrounding areas. Excess grease and dirt on external surfaces acts as an insulator and prevents heat dissipation. Additionally, excess grease on the external surfaces and floors can introduce a safety hazard to personnel.

For more information please consult the Technical Topic titled "Regreasing rolling element bearings."

Bearing manufacturers frequently recommend the amount of grease to apply to a bearing by weight or volume. The grease gun can be calibrated by counting the number of shots to dispense a known amount of grease.

Unfortunately, there's no one single answer, because there's a long list of factors that influence relubrication frequency.

Generally, the smaller the bearing and faster the speed, the less frequent the interval for relubrication with grease. Larger, slower bearings require more frequent relubrication.

Different types of bearings require different relubrication frequencies:

• Radial ball = base interval
• Cylindrical roller = 5 times as frequent
• Thrust-ball and roller = 10 times as frequent

Follow these steps for bearings equipped with fitting and drain:

1. Remove lower drain plug; clean out any hardened grease.
2. Wipe the grease fitting clean.
3. Pump grease into the fitting until old grease is purged and new grease appears. If it is safe and practical, it is preferable to run the machine while performing this task.
4. While the drain plug is removed, allow the machine to run at operating temperature. This allows the grease to expand and forces the excess out the drain orifice, thus relieving the internal pressure. The excess grease will cease draining when normal pressure in the bearing housing is reached (approximately 10 to 30 minutes).
5. Clean and replace the drain plug.

For more information please consult the Technical Topic titled Regreasing rolling element bearings.

Follow these steps for bearings equipped with fitting and no drain:

1. If safe, remove fitting while equipment is running at operating temperature to allow any purging of excess grease in the bearing.
2. Clean and replace fitting. Pump a limited quantity of grease into the bearing to avoid rupturing the grease seal.
3. Remove the fitting and allow the equipment to run at its operating temperature for several minutes to purge excessive grease. If no grease purges, the bearing was most likely very dry; this requires repeating steps 2 and 3 until excess grease purges.
4. Replace the grease fitting.

For more information please consult the Technical Topic titled “Regreasing rolling element bearings.”

Where bearings are subject to contamination, more frequent relubrication may be necessary.

Contamination will lead to unusual operation such as hot, noisy, vibrating or leaking bearings. Be sure to spot, report and act on those.

For more information please consult the Technical Topic titled “Regreasing rolling element bearings.”

An insufficient amount of grease could lead to bearing failure due to lack of lubrication. On the other hand, over-lubrication can also lead to bearing failure and cause problems due to migration of the lubricant into the windings.

Where bearings are subject to contamination, more frequent relubrication may be necessary.

Contamination will lead to unusual operation such as hot, noisy, vibrating or leaking bearings. Be sure to spot, report and act on those.

For more information please consult the Technical Topic titled “Regreasing rolling element bearings.”

Where bearings are subject to contamination, more frequent relubrication may be necessary.

Contamination will lead to unusual operation such as hot, noisy, vibrating or leaking bearings. Be sure to spot, report and act on those.

For more information please consult the Technical Topic titled “Regreasing rolling element bearings.”

During application, first check the amount of grease in the bearing by removing the fitting or grease plug and see if any grease is released. Then check the bearings and seals for any excess leakages.

For more information please consult the Technical Topic titled “Regreasing rolling element bearings.”

Yes, with the following conditions:

• If the amount of oil is small, covering only low spots in the surface of the grease.
• The grease readily absorbs the oil upon stirring.

For more information please consult the Technical Topic titled “Grease static oil bleed.”

A bearing should never be greased more than two-thirds full – leaving one-third air space – to allow for optimal operation.

Refer to the bearing builder manual to determine the exact grease quantity required.

Store your bearings in their original packaging. The best ways to store bearings is horizontally in a dry place and in their original, unopened package. Never place bearings on a dirty surface.

Rotate your bearings while they’re in storage. For greased bearings, periodically turn over sealed and shielded bearings to prevent the grease from settling on one side.

Use identical bearings for replacements. If needed, contact your authorized bearing distributor or manufacturer for interchange information.

Never wash new bearings before installation. The bearing manufacturers take great care to package and ship bearings that are dirt-free and ready for lubrication. There’s really no need to wash them or remove protective slushing compound.

For more information please consult the Technical Topic titled “Electric motors – care & maintenance.”

Excessive noise, vibration and temperatures. Assuring proper vigilance for these signs will go a long way in maintaining your operations. Condition monitoring instrumentation is available to help you spot bearings in poor operating condition.

For more information please consult the Technical Topic titled “Electric motors – care & maintenance."