Grease for bearings

Hello TFers,
What kind of grease are you using for your shaft bearings?
I have 2 universal join coupler plus a pillow block bearing that needs lubrication via grease fittings. I read that molydisulfide grease is the preferred choice. PO was using standard bearing grease. Any input on this?
I need also to grease my rudder shaft via 2 fittings on the rudder plate/post outside. I do it before splashing in spring. Any input on the best grease for this too?

L

Greetings,
Mr. L_t. Wheel bearing grease is "waterproof" but your applications will never really see water. I see no harm in continuing to use what the PO was using. There may be more enlightened opinions...

from Machinery Lubrication:

Greases containing moly are recommended for roller bearings subjected to very heavy loads and shock loading, especially in slow or oscillating motion such as found in universal joints and CV joints. If such greases are used in high-speed bearings, problems can be experienced with roller “skidding” where the bearing roller fails to rotate through the full 360 degrees due to reduced friction. As a result, the roller develops flat spots, and its service life is reduced.

In addition, CV joint grease is often manufactured to NLGI Grade 1 and would therefore not be suitable for automotive wheel bearings.

So, NO Moly di sulphide grease for pillow blocks or any other high speed applications.

I believe grease labeled as "Marine Corrosion control and Trailer wheel bearing grease" would be a good choice. Typically "Red" grease. It sounds like what has been used by the PO.

One thing you must be careful of when changing grease types is mixing different types of grease "bases". Some types of greases are not compatible with others. Look up "Grease compatibility chart".

Ken

I would continue to use what the PO was using. Some greases do not mix well and turn to "mud" which will not cool well.

Agree that you should continue to use what was used. Mixing greases can cause trouble as jleonard described. May not but why take the chance.

Absolutely nothing wrong with the typical lithium based greases which is likely what you have.
Hopefully you have an old tube kicking around from the P.O. It needn't be the same mfg although that would be ideal, just the same type.

Thank you all, I will stick with what was used before, simple bearing/chassis grease.
Another question, is this common to have a rudder support with grease fittings? I know my whole setup is out of ordinary (like having universal joins between the tranny and the rear shaft) but was wondering if it was something seen on some boats? My rudder shaft does not have stuffing but have grease 2 grease fittings used to fill the post tube with grease.

L

I have a grease fitting on the collar above the stuffing box.

kchace said:

I believe grease labeled as "Marine Corrosion control and Trailer wheel bearing grease" would be a good choice. Typically "Red" grease. It sounds like what has been used by the PO.

One thing you must be careful of when changing grease types is mixing different types of grease "bases". Some types of greases are not compatible with others. Look up "Grease compatibility chart".

Ken

Click to expand...

A few clips on greases:

Aluminum complex greases are truly waterproof.

Lithium, lithium complex, calcium sulfonate, calcium complex, and bentone based greases are not waterproof.

Calcium complex typesare good at resistance, but the aluminum based are the only water proof greases in the bunch.

Be aware of age hardening after 2-3 years, so cycle new grease in accordingly.

Also look at the grease. If a moly grease looks gritty/sandy and not mirror-like when wiped with your finger, the moly is not fine enough to work as a backstop lubricant.

In all cases, oil is the main lubricant, making up 75-95% of the grease by volume.

None are compatible with each other long term., so where possible, clean old mystery grease out first.

Bentone (clay) greases do not play well with any others with immediate degradation on mixing.