Mixing U Joint Grease ?

[George House]

I researched past forums but no one asked/answered this. Learned a lot about moly... non moly, zerk fittings, etc. I recently bought a ‘14 runabout and changed the oil just to have a time frame of new oil. Also want to grease all 5 grease cups. I unscrewed the large U Joint grease cup and spied a brownish grease. I like Mobile red non moly inserted with zerks and am wondering if it wouldn’t hurt to mix the two types. I’ll now remove the large grease cup, wash it in gasoline, tap it and install a zerk. Should I look for/buy a tube of this brownish non moly grease or can I mix it with my Mobile red ??... thank you

[Jugster]

I had a bad experience with mixing two kinds of grease. The grease liquified to the consistency of motor oil, leaked out of my grease-gun and made a great, big mess on the floor of my garage. I don't think there's anything to be gained by mixing two kinds of grease. Stick with whatever you've been using and it won't hand you any surprises.

[TWrenn]

Seems to me at one time there was "a list" of the various greases that CAN be mixed together? Or did I dream that?

[TXGOAT2]

I've read that mixing greases can cause problems. I don't remember specifics, if any were provided. In the case of the Model T u-joint, I don't think it would be a serious problem, since the speed and load factors are fairly low, and the unit is not sealed and not dependent on a very small amount of grease over a long service interval.


Most Model T ujoints run in a mix of grease of one type or another and motor oil. The motor oil carries assorted additives which may or may not play well with assorted greases.

Given the large amount of grease available to the ujoint, the low operating speeds and loads, the near certainty of oil contamination, and the necessity of frequent additions of more grease, my opinion is that mixing types of greases when changing brands or types of grease would not cause any problems in a Model T.

I like moly grease for most ujoints, but in the case of the Model T, the moly additive could possible cause issues if some of it got into the motor oil, where it might affect the magneto or the function of the transmission bands. For that reason, I stick with the thick red grease, which seems to give good results for many users.

[Art M]

It is the different kinds of soap in the grease that don't allows get along. I use lithium based grease because it seems be be the most common and it seems to work well.

I don't have access to lubrication engineers like it did before I retired 20 some years ago, so I can't go into detail about the different soaps in grease.

Art Mirtes

[rnkugel]

Don't remember where I got this. Have it saved on my computer.

[Bryant]

Some greases will mix together and then harden probably don't want that either.
bryant

[Steve Jelf]

I agree it's probably best not to mix greases, for the reasons cited, but I'd also say the thicker it is, the better. One of the functions of grease in the U-joint ball is to act as a dam that diverts leaking engine oil from running down the drive shaft tube and into the rear axle.

[George House]

You mean the ring and pinion isn’t lubricated with 30 W non detergent Steve ??... just kidding. Thanks for all responses. I’ve decided not to mix grease - just take the full grease cup cap to a trusted auto parts guy and buy a tube of the same non moly stuff.