So can you make a suggestion of what grease is recommended on OEM crank seals since that seems to be the standard suggested seal?
Yamaha only lists water resistant grease.
Also if the manual is in error as to the seal orientation that would be a good note to make sure they go in correctly.
Ok, while, BK is right, any type grease will work? And as I said, any lube is better than no lube at all.
Lets take it a step further, but Im not going to go into great detail. I have been thru more Bearing clinics
Than I care to think about. Most of these clinics are centered around installation, and service life which includes grease / lube intervals. Seals fall directly into this due to their close proximity to the bearing. These clinics were instructed by SKF engineers.
First off there are two types of Radial Lip Seal materials. Cheap aftermarket seals, like SBT / WSM seals in the watercraft world are made of Butyl rubber. The better seal, or OEM branded seals are made of EPDM, or a thermoplastic synthitic material. Both seals are effected by the grease / friction heat / water slightly differant.
Traditionaly, most bearings / seals are lubricated by a lithium base or Lithium complex grease. This is fine for 99% of the applications. How the grease works is, as the shaft spins, heat is produced at the friction point. The grease in the immidate area turns liquid or into an oil substance. The oil rolls around the lip keeping it cool, and lubricated.
The butyl rubber type is partly broke down by the lithium ( mineral base) and softens. Then hardens when cooled. This cycling hardens the seal and they start cracking in fairly short order, thus have a short service lfe.
The oem seals (EPDM) is not effected by
the heat or lithium and has a much longer life
Lubricants are constantly evolving. Enter Synthitic based. For this, I have become a big fan.
The synthitic Based Silicon greases are even better IMHO.
These synthics handle very high loading applications, have high heat ranges, without thermal breakdown
Long service life intervals, and are highly water resistant.
I personally have been using the synthics for close to 10 years. I have enjoyed very good results.
And have not experianced any seal lubricant related failures.
Two other things worthy of mention. I change seals at every teardown / crank inspection & Never reuse seals.
I always glue the seals into the cases with the case sealant . Espically the rear output seals.
As for branding? There are many. I personally like Mobil Lubricants. But, most all name brands carry high ratings
You do get what you pay for! I dont buy my motor related stuff at Walmart!
For the oriantation question? I made a joke as BK mentioned ........ “Tits Out” If you have ever installed a set of seals
You will know exactly how the joke is refranced !!
Hope I answered what you were looking for?
Ski ya, Paul