How much does it hurt if the grease for the wheel bearings doesn't contain moly?
The only high-temperature lithium base grease at the nearby parts store is Exxon Ronex MP (green), which doesn't contain moly, unlike some other verisions of Ronex (EP, not stocked). But they also have high-temperature aluminum base grease with moly in it. What's the difference between lithium- and aluminum-based grease? Which is better?
I found a couple of message threads about this at
An interesting dissertation, but to me the key phrase was this one--
"MoS2 will survive pressure into the neighborhood of a half million PSI and two thousand degrees F. in an oxygen depleted environment with practically no corrosion and erosion"
In an 'oxygen depleted environment' it says. And where do we find one of those?
I find moly grease in my front wheel drive rezappa joints, and I suspect that's a pertinent application. But moly in engine oils has always been a no-no in my opinion. Moly contains sulphur, and when sulphur oxidizes you get the possibility of corrosive acids forming.
Where do you live? Surely there is more than one Parts Store in your area.
Is that why Exxon quit putting moly in some of its motor oils several years ago or why I was told to use plain lithium grease and not moly-lithium as an engine assembly lubricant?
Just use one "base" grease with or w/o moly as long as it says it is for your appl. e.g. disk brks/hi-temp. etc. By base I mean the "ums" (alumin-, bari-, sodi-, lithi-). Usually you will find that lithium based greases are the most common. NEVER MIX THE "UMS" because they are not compatible, according to what I was told MMA by the tech. at Witco Chem.(Kendall/Amalie/QS lubes). If changing bases, EVERY trace of the old lube must be removed. Cleanliness is otherwise very important also in anti-friction bearings. Never use a diff. base than is recommend. by the car manufacturer, if any.
The F-111 fighter/bomber uses MoS2 grease for its wing pivot points; very high loading in an oxygen deprived environment. John
No parts stores close by, just Pep Boys, Checker (Shuck's, Kragen), and AutoZone. But at Pep Boys I found some Sta-bil brand disk brake grease with moly and an "aluminum complex" base, which
Those are for the caliper sliders I think, not for bearings.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT'sDepends on Manufacturer - Ford specifies moly containing grease for front (and rear if you have disks) wheel bearings - bearing is in rotor on Fords. GM does not. If it makes any difference, most of the guys I race with use moly or synthetics on all of the bearings. And you should not mix grease types (blend would be a better word). Find a good synthetic grease (I run krytox in the bearings on one car - try to find that at an auto parts store - $1K/lb - got it as a present from a bud a JPL - my bearings should never wear out according to Dupont), and your worries shold be over - just buy a couple of tubs and that should last you a while.
Andrew
Sue D Nim wrote:
I'll clean out everything when I do the bearings, but I was worried that if a garage ever serviced the vehicle, such as to turn the rotors, they might just add grease. They'll almost surely use lithium-based grease, but it seems that aluminum-based grease won't have trouble with it:
Hardly. Highest loading will occur at take off with full fuel and bomb load, at low altitude. Loading at high altitude with wings folded back will be lower. And in neither case will there be much heat involved.
Service Manuals for several vehicles american, japanese, and french vehicles do warn against the use of moly grease in wheel bearings.
The movements in the CV joints lubricated with moly grease is very limited and oscillatory at most. They do not resemble the movement in a wheel bearing.
In the Mobil website, they mention that the Moly in Moly greases may under some circumstances become separated from the soaps in the grease (thickening agents) and it may clog the gaps intended for proper grease recirculation. Moly grease is best used for low precision bearings.
The moly in moly greases is also intended as back up lubrication in case the grease dries out, and ideal applications are oscillatory movements e.g. splines, bedways, chains, rzeppa cvj etc. Never the less, most tripod CV joints do not use moly grease.
In general, it is best to follow the manufacturers advice.
If it were my vehicle, I would not use moly grease for wheel bear> How much does it hurt if the grease for the wheel bearings doesn't > contain moly? >
Uh, the lube is only needed when the wings move around their pivot pins, and they can move at any altitude, any speed, any loading. John
In message , larrymoencurly writes
Where have I gone wrong, I have been brought up on Copper based grease for all high temperature applications?
This:
I was told that silicone and aluminum based greases are good for sliders because they're waterproof.
Sta-lube has a separate product for caliper sliders, "BRAKE CALIPER SYNTHETIC GREASE:
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