Grease Testing

[Ken45101]

Thanks for the chart and the url reference. If I am reading the chart correctly, I guess that explains why polyurea sometimes has a bad rep for compatibility yet Deere rates their Multi-Purpose SD Polyurea as generally compatible: there are two types of polyurea and presumeably Deere is using the shear stable compatible type.

Two thoughts:

-- Of course grease of any sort is better than no grease

-- Sticking with one broad use grease is probably better than jumping around from one tube to the next and wondering what you have and how compatible it may be.


How many of us have different grease guns with different types of grease for different applications? Is there any real value in that?

Ken

 

[Mace Canute]

How many of us have different grease guns with different types of grease for different applications? Is there any real value in that?

As a general rule moly grease is not good for rolling element bearings, so you probably should have two different grease guns if you want to use a moly grease in certain places.

 

[John Morgan]

As a general rule moly grease is not good for rolling element bearings, so you probably should have two different grease guns if you want to use a moly grease in certain places.

Mace...How do you figure? Under heat and pressure Moly adheres to metal components creating a protective barrier, reducing friction and increasing the life of the bearing.

What is there about Moly that would be bad to use in a rolling element bearing?

 

[Mace Canute]

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. I've heard that it is related to the particle size of the moly used but I can't find anything definitive on it at this time. Caterpillar did have this to say about their own moly grease...from http://www.biodiesel.org/pdf_files/OEM Statements/2005_OEM_CatVersion9.pdf page 17/78

In addition, the Moly in Cat Ultra 5Moly Grease is a special grade that has a median particle size of 3 microns in order to meet the special requirements of some rolling element bearings.

From Moly??? - Bob Is The Oil Guy

Molakule, I have 6 inches of scar tissue on my derriere from having once recommended a 3% moly grease for all applications for a coal company. Within a few months the company began having u-joint failures galore! On inspection of the U-Joints we found that the moly had centrifuged to the outer portions of the needle bearings, preventing new grease and replenishment oil from reaching the outer portions. In fact the outer portions of the needles had been eroded away from the pure moly! Thus the failures. I then switched them from one universal to two specialized. i.e. Moly additized for the plain bearings and non moly for the non friction bearings. Problem gone.. That was 10 years ago.... I still have the failed U joints in our warehouse as a reminder.

and

I have 5 product data sheets for 3% moly greases from 5 different grease manufacturers that state "for use on heavily loaded sliding surfaces only. Do not use this moly additized grease in non-friction type bearings as the moly will cause premature bearing failures" or some variation of those words.

Also from Engine Bearing Grease

The reason moly is NOT reccomended for ball bearings is because the moly can build up on the race surfaces and reduce the bearing clearances enough to cause bearing failure. Some years back the Model A Ford club reccomended a moly grease for the rear axle ball bearings. There was a rash of axle bearing failures traced to this moly build up on the races. It is in fact an irregular build up of the moly and forms patches on the races and it had the same effect as dirt in the bearing.

And from lithium grease - Page 2 - PeachParts Mercedes ShopForum

Here are a couple of quotes from Exxon regarding their Moly EP type greases (emphasis added):

RONEX EXTRA DUTY MOLY 2 is recommended for high load applications at slow-to-moderate speeds, including applications in the paper, construction, and mining industries, as well as off-highway vehicles operating at 35 mph or less. RONEX MP, with its much lower base oil viscosity of 767 SUS, is designed to meet a wider range of high-speed industrial and automotive bearing applications, including wheel bearings in on-highway use.

Beacon EP 2 Moly is suitable for plain bearings and gears. It also can be used in rolling contact bearings, but is not generally recommended for high-precision rolling contact bearings because of the possibility of molybdenum disulfide building up in the clearances.

(Bold added by me).
I think one should error on the side of caution and not use a moly grease in a rolling element bearing...just in case.
Moly grease can be great for plain bearings (bushings) though.

Did you know...molybdenum disulphide in the presence of water can cause electrolytic corrosion.

 

[John Morgan]

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.

Old stories about lubricants linger for decades. Technologies change and improve. I still get statements about how you can't switch synthetic and petroleum oils. It doesn't help that a great majority of lubricant sales people have very little technical knowledge of their own products so they make up a bunch stuff when challenged by old ideas.

 

[Mace Canute]

Good to know, John. :thumbsup:

 

[brucew44guns]

With that said, I'm lazy and would rather have only one type of grease on hand. So I pick whats best for the sealed joints in my trucks, and stick to that. In that case, I like a good moly grease with a Timken load test of at least 80 lbs, but better would be 100 lbs. The soap base doesn't bother me much as its job is to hold the lubricant, but I try to stick with one type to avoid incompatibility.




I know a little about greases, but quite frankly I don't know of a grease with an 80, or 100 pound Timkin Rating. I sell a 70 pound rated grease, and quite a few at around 50, but may I ask who has a 100 pounder?, just curious?

 

[Mace Canute]

Texas Refinery Corporation's #2 grade 880 Crown & Chassis grease has a 100 lb Timken OK load rating. Their #00, #0 and #1 grades of 880 have an 80 lb Ok rating as does their Moly 880 C&C #1 and #2 grades. Their Paragon 3000 has 80lbs for their #1 grade and 100 lbs for their #2 grade.

 

[brucew44guns]

Texas Refinery Corporation's #2 grade 880 Crown & Chassis grease has a 100 lb Timken OK load rating. Their #00, #0 and #1 grades of 880 have an 80 lb Ok rating as does their Moly 880 C&C #1 and #2 grades. Their Paragon 3000 has 80lbs for their #1 grade and 100 lbs for their #2 grade.

Thanks for that info, yes--I know of TRC C&C, a very nice looking tacky red grease that is **** for tough. I did not know the Timkin on it though.

 

[LD1]

As a general rule moly grease is not good for rolling element bearings, so you probably should have two different grease guns if you want to use a moly grease in certain places.

Thats pretty much what I have always heard.

I personally use a good moly (black) for things like pins and bushing on the loaders and backhoes, bushhog tailwheels, etc.
And I use a good (usually synthetic) NON -moly grease for the roller/ball bearings. Currently am using SHC460, but have also used XHP222 (blue) and sta-lube sta-plex EP (red) in the past