A question pertaining to nomenclature on vintage bus lubrication charts

[dtcerrato]

Referencing particularly vintage GM busses but maybe true for many other makes, the lubrication charts that are usually a supplement to "da book" (maintenance manual)...
Of over 45 lubrication fittings through out the entire bus the majority of fittings call for "C" or chassis lubricant.
Only 4 fittings call for "S2" or 15% sodium soap grease
These 4 fittings are: front & rear wheel bearings, clutch pilot bearing, clutch release bearing, and generator bearings
With our original generator on the bench for repairs & upcoming clutch release bearing & wheel bearing replacement - one would wonder what those genius engineers were thinking to single out a particular type of lubricant different to the majority for these few components
Is such a grease (15% sodium soap grease) available today?
Could anyone shed some light on this subject matter?
Thanks

[lostagain]

A good quality bearing grease nowadays is much better than whatever was prescribed 60 years ago. I use whatever good grease I can find and apply it everywhere. The more often the better.

JC

[luvrbus]

The S2 was the white Lubriplate grease that has been around for a 100 years,I haven't used any soap based grease in 25 years it is made from the the salt from fatty acids.I have used the Mobil 27 or 28 for years now but there are other brands and class of grease that will work besides the S2 rating   

[TomC]

Synthetic wheel grease is a good choice.