Pros/cons of moly in wheel bearings?

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I have been using the amsoil spray grease for my wheel bearings, but I was wondering if there would be a benefit to running a moly grease in the bearings. If CV Joints require moly, how come wheel bearings don't? It seems they are under similar stresses.
 
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They work differently. CV joints slide and wheel bearings roll. No harm in using moly grease in wheel bearings but there is no compelling reason to use it. The important thing is that the grease be intended for wheel bearing duty.
 
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 Originally Posted By: Johnny
What kind of wheel bearings have you been using spray grease in?
I didn't have the nerve to ask that question because I thought I might be missing something obvious to more knowledgeable people. However, what kind of wheel bearings have you been using spray grease in?
 
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I would personally contact Amsoil about your application of this product. I personally would not use a spray grease for the front wheel bearings of my car. I will try to get Pablo in to this conversation.
 
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Wow spray grease for wheel bearings, sounds like a dangerous thing to be doing. AD
 

adambrouillard

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It says right in the description that it is usable for wheel bearings. Anyway, I have been doing it for years with no problems.
 
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 Originally Posted By: adambrouillard
It says right in the description that it is usable for wheel bearings. Anyway, I have been doing it for years with no problems.
Cool, beats packing wheel bearings I guess. I have a tool for it, and just pump grease into them from the grease gun. AD
 

adambrouillard

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Yeah, i like it because it's easy to relube the bearings without pulling them from the hubs. I just pull the seals, flush and respray.
 

Kestas

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As Pablo said, allow the carrier to evaporate... especially before installing the seals. Once the seals are on, the vapors can't escape. Without knowing how long it takes for the carrier to evaporate to the point that it doesn't adversely affect the grease lube properties - one week maybe? - I can't recommend using a spray grease for sealed bearing application.
 
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Ford requires moly in their wheel bearings, that would indicate to me that there is a reason for it. However, I see many people use non-moly grease in Ford wheel bearings without problems.
 
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I do not have any test data to substantiate the following but have always understood this to be the case regarding solid "moly" (Molybdenum disulfide) as found in greases: ****Do NOT use moly greases in wheel bearings or in the steering head bearings. Moly tends to change to stiff flaky bits if used in those roller bearing applications. As a general rule, do not use moly containing greases, oils, etc., at any place there is rotational speed differences, or in ball bearings, needle or roller bearings, and most sleeve bearings. Moly is GREAT for most SLIDING surfaces. It might be better to think about the application and then make a decision. Why do you need moly in this application? For wear protection? For lubricity? There are plenty of established greases that meet specs such as NLGI GC-LB that do not contain moly and function very well in wheel bearings. Additional thoughts?
 
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salesrep

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 Originally Posted By: 68redlines73
I do not have any test data to substantiate the following but have always understood wheel bearings. Additional thoughts?
Test results and real world results have determined that moly grease performs just fine in wheel bearings.
 
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 Originally Posted By: salesrep
 Originally Posted By: 68redlines73
I do not have any test data to substantiate the following but have always understood wheel bearings. Additional thoughts?
Test results and real world results have determined that moly grease performs just fine in wheel bearings.
+1 I think the caution might come from using CV joint grease in wheel bearings?? Where's Kestas when you need him?
 

Kestas

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I'm standing at the sidelines. I'm not an expert on all lube issues, so please correct me if I'm wrong. What I do know is that wheel bearings require EP additives in the formulation, and the grease must withstand the elevated temperatures produced from the nearby brakes. MoS2 (moly) is considered an EP additive. I believe there are other compounds that are considered EP additives. This would suggest that moly is not a 'must have' in any application. The other issue is how elevated temperatures affect moly. If temperature is too high, or if the gease isn't formulated to suppress activation at elevated temperatures, sulfur compounds can attack the base metal. I don't know if wheel bearing temperatures are high enough to activate moly for it to attack the base metal.
 
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 Originally Posted By: salesrep
 Originally Posted By: 68redlines73
I do not have any test data to substantiate the following but have always understood wheel bearings. Additional thoughts?
Test results and real world results have determined that moly grease performs just fine in wheel bearings.
Please provide any published info you have.
 
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