Be Aware Of the Grease in Your Bearings
A few weeks ago, I had a customer call and asked me how to identify the grease in a bearing?
I asked the customer to provide me a picture of the bearing grease and the label on the box. I was able to identify the grease in a matter of seconds, but this scenario was more involved than it may have seemed on the surface.
Dive A Little Deeper
I started my bearing career back in 1999 and this was about the same time that all the major bearing manufacturers were switching their standard industrial aftermarket grease to Mobil Polyrex EM or similar formulation. A study was released stating
Polyrex EM, a polyurea grease, lasted three time its competition with a very good temperature and viscosity range. Polyrex EM is very identifiable, a beautiful blue. Three big questions came out of this one question:
- So where did this bearing come from with the incorrect grease?
- Was it compatible with Mobil Polyrex EM?
- How do we know what type of grease is in our bearings?
Picture 1: Mobil Polyrex EM in bearing
Answers to 1 & 2
Question 1 leads us to Bud’s Take Issue 26: Grey and Counterfeit. Was the distributor authorized and did the bearings follow proper channels into the market? The best way to answer this question is to know your distributor partner.
Question 2 leads us to Bud’s Take Issue 14: Grease Compatibility. My solution is simply: don’t mix!
A Little Focus on Question 3
The question: How do we know what type of grease is in our bearings? This can be answered multiple ways.
The easy answer is the same answer used for question one, know your distributor partner. A factory authorized distributor can obtain these answers because of their relationships with their suppliers.
Another, more difficult method is to be versed on the nomenclature of each bearing manufacturer.
SKF denotes the Polyrex EM grease in two ways. Polyrex EM is part of the EM or the electric motor bearing quality specification. They also have a specific grease code, GJN.
Schaeffler (FAG) designates Polyrex EM by the code L038. All products made in the United States are standardized to Polyrex EM so the code is omitted.
Koyo designates their greased bearings by the letter G and then a specific code for each type grease. The XM designates Polyrex EM.
Nachi designates Polyrex EM by the code XM.
NTN denotes the Polyrex EM grease in two ways. Polyrex EM is part of the EM or the electric motor bearing quality specification. They also have a specific grease code, L627.
Conclusion
The scenario at the beginning of this article may appear harmless but could have resulted in a premature bearing failure and extended downtime. If you don’t know what grease is in your bearing how can you be certain the end user will not re-lubricate with an incompatible grease? Approximately 50% of bearings fail due to a lubrication issues, the last thing we want to do is exasperate the problem. Knowing which grease is in your bearing will help you avoid self-inflicted lubrication issues.
This particular issue should never occur. I suggest you get to know your distributor partner and see if they are a factory authorized distributor for your preferred bearing brand. I would ask if they can support your basic technical issues.
If you have any questions, comments, ideas for future topics please feel free to contact me directly at [email protected]