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Discussion Starter #1
I was on the FJ cruiser forum and the topic was "greasing your Zerks!".Someone made the comment not to use Moly type grease for needle bearings?.....I guess some of the u-joints / slip yokes may have needle bearings there???.So,if you know why Moly grease would harm needle bearings,please chime in!.
 

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This is all I could find (it was on a tractor forum)



I've heard the moly can build up and reduce the clearances in a rolling element bearing to a negative number. When that happens, the bearing self destructs. It doesn't happen every time but it does happen and when it does, it's the last thing anybody ever suspects for the cause of the failure.



Then I found this to counter the first statement



Virtually everyone of those references are from old technology from Industrial grade Moly at 7 microns. The largest percentage of lubricants fortified with Moly in todays industry uses the 3 micron Moly. Schaeffer's grease uses a Technical grade Moly at .7 microns. At that grade, the protective layer that is built is a micro-fraction of a human hair. It is not mechanically possible for this Moly to throw tolerances off in these bearings or result in corrosion. The "disulfide" aspect of Moly prevents this. Sulfur is an anti-oxident. The corrosion you refer to occurred from raw molybdenum in low quality products trying to compete by offering low cost "Moly" greases.
 

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I would submit that you could drive a truck through the clearances in our swingarm bushings, that on their worst day in life they never get hotter than ambient temp and it you're staying on top of your maintenence it isn't physically possible for any of the above (if true) to ever issue on swingarm or steering bearings. Most of the conjecture about moly concerns its use in high temp, high rpm situations such as car and truck wheel bearings and drive shafts.
 

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Discussion Starter #4
In the FJ cruiser forum mentioned above,they were speaking of greasing,through the zerks,the drive line etc. I suppose one would have to get a masters degree in Chem. Eng. inorder to actually know the true workings of grease in mechanical units?. Thanks for the responses!.
 

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I certainly claim no master's degree in the subject And generally tend to regard all oil discussions as one of the more inexplicably predictable and humorous aspects of motorcyvling in the internet age. Just pointing out that the requirements of a swingarm bearing are pretty minimal.Moly is cheap, common and almost overkill fot the purpose.
 

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Discussion Starter #6
After alittle bit more research,I believe the demonization of Moly was from years past?.It was customary for some moly grease to as high as 7%....now-a-days it is at or below 3%,some well below,as in .7%?.Folks will have to make up their own mind though.
 
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