10 things need to know when using bearing: When using bearing users encounter some problems such as: How to select bearings, How to choose the suitable grease for bearing/ Is it nescessary to add grease for 2-cap bearing? How to correctly fit it? The everage life expectancy of bearing?How to know symptoms of broken bearing? What methods to know the working status of bearing? How to measure the bearing erosion ? Why using staper beaing which is fitted on the sleeve  make it broken quickier? Some recommened remedies.What should be done when the inner ring or outer rings rotates on the sharft.To answer  these questions, please read the following article:  

Replacing bearing of air compressor 

1. How to select the bearing 

See the method of bearing selection here

2. How to choose the suitable grease?

Refering to manufacture's manual to choose the suitable grease

(See how to choose grease for SKF bearing here)

3. Is it necessary to add grease for 2 cap bearing?
The bearing has available 2 steel cap  (-2Z) or two rubber seals (-2RSH or -2RS1) have been pre-lubricated with a suitable type and amount of grease to ensure that these bearings operate to the end of expected life of the bearing.
Therefore, we should not pry the rubber or cap to add more grease, this does not make the bearings work better but may damage the bearings because when disassembling the can disable them , essive grease will make the bearings heated. Moreover added grease may be incompatible with the recommended grease that has been introduced by the manufacturer.
However, in some cases such as applications with vertical or rotating external requiring  special lubrication,  please contact the supplier for details.

4. How to correctly bearing?
Contact to supplier so that you can fit them corectly or you can watch this video:

5. The average of life expectancy of bearing
Bearing life in various applications is different.Technically, bearing life is determined by rotations, changes depending on: load capacity, working temperature, environment ( dust, moisture, chemicals..)
These are some symptoms of broken bearing:
-Tenperatura of baring support is abnomal increase.
-Abnomal noise
- Vibration is abnomally increase

By periodically monitoring the parameters and mentioned  descriptions , users can evaluate and predict the operating status of bearings

7. Method to know working status of bearing in using
Mentioned in section 6, bearing status is reflected through pramaters such as : temperature, noise, vibration. Periodically monitoring these will help users evaluate bearing status. Curently, the best effective way to monitor and predict the failurre of bearing is measuring and analizing vibration of bearing.  

Note: Beside  you can refer to  diagnose of  bearing failure

 8. How to measure the bearing erosion.

Every bearing has standardized slit. Measuring, checking requires specilized equipments with high accuracy. The "lead pressing" method applied in somewhere is recommended not to use because of inaccuracy. Normally, after long time using, the erosion on the surface of rolling gloove  is not the same. The peel on the rolling gloove is the main reason causing the failure of bearing if the lubrication will not well-guaranted. Evaluation by feelingdo not allow users to undervest correctly bearing status. 
Curently, monitoring bearing  working status by measuring, analizing vibration and following the frequency of failure is being applied popular with specilized measuring, analizing equipments.

9. Why using staper beaing which is fitted on the sleeve  make it broken quickier? 
Repairing staper bearing is often quickier broken causing due to tightening the screw, the bearing has not enough required inner gap. There is the remaining inner gap after proper mounting.

10. What should be done when the inner ring or outer rings rotates on the sharft
The cause of this phenomenon is due to:
- Bearings are stuck (cannot run) due to loss of internal room or improper lubrication.
- Improper mounting. As a result, the bearing slowly rotates on the shaft when working gradually make the bearing rotate evenly in the shaft. The best method is to replace the shaft. In case it is not possible to replace it, the method of re-welding and re-processing for correct mounting can be used. However, the care must be taken during machining to avoid offset.develop gradually to make the bearing rotate evenly in the shaft or on the drive