"Moly" Greases

[John R]

I have read that "moly" fortified greases should not be used in high speed/hight temp applications(wheel bearings?) , that they are for high load/low speed applications. It was said that moly disulphide becomes reactive at high temperatures and can cause corrosive wear in metals. Is this the case? Bob, Terry, care to comment?

 

[widman]

I have read and heard arguments both for and agaist moly greases. most are for them. This week I had the wheel bearings and brakes checked on my 95 4Runner. They changed the pads. The bearings were in perfect shape with 3 years - 50,000 miles - of 85% dirt and gravel roads with a Bentonite/moly/graphite grease. What little time it spent on asphalt was at 70mph. The last time they had been greased was after the river took it downstream. At that time the grease had 30,000 miles, 28 hours under water, and 30 days of towing back to civilization. At 110,000 miles the wheel bearings are original. Greased at 30, 60, and 110. That must say something for Moly greases.

 

[frule]

What are some recommended greases that contain moly?I'm currently using Valvoline synblend with moly.

It seems that I remember Bob saying to use an "aluminum" based grease with moly,but I couldn't find one at the usual outlets(Advance,Autozone,Pep Boys),hence the Valvoline.

 

[BOBISTHEOILGUY]

quote:

---

I have read that "moly" fortified greases should not be used in high speed/hight temp applications(wheel bearings?) , that they are for high load/low speed applications. It was said that moly disulphide becomes reactive at high temperatures and can cause corrosive wear in metals. Is this the case?

---

John, that is incorrect.. The thing about speed factor is determined by the amount of tac used. The heavier the tac, the slower the bearing application. The heavier the tac normally means less oil which is not as much of a concern for slower applications. The lighter the tac is for higher speed bearings.

Moly disluphide does not cause corrosive wear but moly disulphate does.This happens to be one of the problems I am concerned with in some of these motor oils like maxlife which too many people are jumping on because of the word moly being used.

Moly is highly resistive to water but will wash out if the complex is not there to sustain it, that is why an alum complex is more desirable than lithium or even betonite types of greases.

 

[Alan Kauth]

Bob, does that mean then that a moly fortified grease is acceptible for use in say an automotive u-joint? If it is used on a Toyota u-joint (a v-8, 4wd Tundra specifically) what would be the suggested greasing interval?

Is there a a Shaeffer grease you'd recommend for that application? I've heard that moly greases shouldn't be used in a u-joint. But maybe the problem is more "using it too much".

Alan

 

[BOBISTHEOILGUY]

Alan,

We had an excellent discussion about this and I suspect there is more to it than meets the eye.

I recommend the 221#2 schaeffers because most any area of the country you can use that in all points of the vehicle with varing temps.

Here was the discussion by GeorgeCLS and myself concerning NF bearing applications and moly.

One thing to keep in mind, there is all sorts of different brands of greases and in schaeffers case, they do blend their grease differently which might be the reason for the difference. I also noticed someone posted a chart for grease complex compatibility and on theirs it shows the alum complex wouldn't mix with other types of complex, which is incorrect when it concerns schaeffers as it is fully compatible with all types of complexes except bentone(clay base). Again, this maybe a difference in blending process as not all formulations are the same. I can say from experience of myself and many other schaeffers reps years of using their greases that it is obvious not all greases are a like even when the base complex is alum and has moly in it.


http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=2;t=000001;p=1#000013