Wheel bearing grease substitutes?

[MMercury]

This topic may have been previously discussed, but I did not see anything on it via the search function.

I was replacing front rotors and when I got to the point of repacking the wheel bearings I couldn't seem to locate any of the seemingly tens of wheel bearing grease containers I usually trip over. If it matters, I have been using sythetics supposedly designated for that purpose. In looking around for the grease, I discovered a large cache of CV joint moly lube and began to wonder whether it couldn't be used for wheel bearing lube too.

Let me explain that I found the wheel bearing grease and used it, but I am still wondering. Common sense tells me that wheel bearings fitted next to outboard disk brakes are probably exposed to higher operating temperatures than CV joints and the bearing loads are probably greater for wheel bearings too. But cv joints are no slouches when it comes to loads - hence the requirement of molydenum extreme pressure lubricant.

So why aren't the two grease types interchangable or, conversely, why is that no recommends using wheel bearing grease to repack cv joints or CV joint lube for wheel bearings?

Thank you in advance.

 

[jhjacobs]

Great question - I hope you get some authoritative responses! For what it's worth I suspect you would be fine with CV grease. I haven't packed a wheel bearing for 25 years but my shop manager always made us use standard white lithium grease. I have probably done 200 sets of bearing this way and I know my E9 logged close to 300K miles and I always packed the bearings with white grease about every 50-75K miles.
OK - go ahead a flame me for this one. :?

 

[Malc]

I think the moly grease is used in CV joints because of the sliding loads. The whole CV joint rotates and the movement in it is the balls and cage "sliding" back and forth. Moly gets quite runny when its warm and the rubber boots help to keep it all in place
Bearings on the other hand have stationary and rotating parts thus the loads are different. They tend not to be sealed so the grease has to stay in place and stay "thick"

I'll get my anorak now :?
Malc

 

[Ed G]

The short answer!-
Molybdenum disulphide (MOSO2) is an extreme pressure additive solid that is added to a grease to give the grease certain properties. If you looked at moly through a microscope the moly particles would look like a deck of cards. Moly performs particularly well like Malc says in sliding applications where you have a lot of back and forth motion and are not generally recommend for higher speeds. Back and forth motions are some of the most difficult to lubricate because that action has a tendency to wipe the surfaces clean of lubricant. Moly, in addition to the typical tackifiers that are added to grease have the ability to stick to surfaces very well and are the preferred grease for these types of applications. Moly is great for splines and such.

Rotating applications like wheels however, are better served by using a standard grease that do not have moly solids. Standard greases do have EP (extreme pressure) additives that give them good load carrying characteristics and hold up better in rotating applications. These EP additives are pretty much standard for today's greases and it is actually difficult to find a grease without them.

Wheel applications, although highly loaded do not rotate that fast, relatively speaking. At 60 MPH your wheels are spinning at about 850 RPM which is considered mid to low speed for bearing capacities. So if you DO use a moly grease, you're not going to experience a failure but the regreasing interval will probably be sooner. The higher the speeds you go, the quicker you will break down the moly EP solids.

And last-
In the industrial world there are more options for greases than your typical over the counter greases. Most all grease you buy are NLGI #2 greases. This rating pertains to the consistency of the grease which in this case is like peanut butter. NLGI #2 would be considered general purpose.

 

[MMercury]

"greasy fingers smearing shabby clothes . . ."

Appreciate the well considered responses.

Funny thing is it may just be that most of the current array of specific greases out there exceed the standards for most of their designated uses.

I wondered why I had all of the unopened CV grease tubes and discovered that a long gone comrade was using some multipurpose semi-synthetic "red" grease for just about everything from wheel bearings to cv joints to lower drive units on the boat. I seem to remember the containers actually said you could use the grease for that purpose, but its been a few years since he moved and I have no idea what brand the grease really was or if its not just my failing memory.

I mentioned memory in that I recall several ex military mechanics who swore by the thinnest "lubriplate" white lithium grease for all kinds of heavier applications, including winches, wheel bearings, lower drive units, helicopters and rebuilt engines. The product was more like a liquid than a solid, and to their credit they never seemed to replace bearings. But they sure did repack them alot! Because of an injury one of these guys helped me reinstall an e-9 driveshaft and double dosed the sliding shaft with the white grease. 10+ years later the driveshaft seems fine (although I have fretted about the grease attracting dirt and becoming abrasive). He used to say only one thing better something space-age called Kryton(?) But that stuff was supposedly more expensive than the machinery it was lubricating.

Assuming, for the sake of argument, one were to repack a CV-joint with grease designed for rolling loads (wheel bearing grease) versus sliding loads(MS02), given "normal" use, how long might the realistically joint last? (Yeah, I know normal is defined as not abnormal ) Too much Dewars or is it Drambuie? :wink:

I guess I ought to also ask are there any lubricants you fellas recommend that are not ordinarily thought of for the purpose you use them?

 

[Malc]

For CV joints use moly, it's cheap enough and is supposed to do the correct job. You could use the other stuff but the life of the joint will be shortened

Other uses.....Er.... well yes....
The red grease your friend used is used in the oil industry for extreme pressure and temperature applications. I have used it on trailer wheel bearings, hinges with no problems. It's also used in Agriculture BP make it.
I also use it for jobs like sticking the collets on valve stems.

Vasaline - wonderful for packing oil pumps in rebuilt engines. Helps with the priming of the system the first time and "dissolves" in the warm oil.

Pipe Dope , Used when the drill pipe is screwed together. Some is grey in colour and has a lot of zinc in it, some is brown which has a lot of copper in it. I have a 25Kg drum of it which I have had for more years than I care to remember and I use it on nuts and bolts. Same as Never - Sieze but cheaper and better quality than the stuff you get in a parts shop.
Malc