G'day MF,
I always wondered Gadge, does water ingress into the bearings after immersion of the axles? I imagine you will find a gross emulsion of axle grease and water after a few crossings.
Yes, water can certainly make it into the bearings, if the diff and bearings etc are up at full road operating temperature when going into the cold water.
It's not so much of a problem at bush track speeds; though water ingress to the diff gear compartment can be, if extended axle breathers aren't fitted.
Regular repacking and diff oil changes are cheap insurance; as a failure in real 'tiger country' used to mean a long walk out, at the least. Often still does, as mobile phone coverage is crap in Vic's High Country, and not many can stretch to a satphone.
Someone told me that the water would just dry out through heat generated from the wheels rolling.
Well, no, as the assembly is sealed with 'lip' type seals, which act as a one-way valve - water can get in, but not out; even if it all gets hot enough to boil the water
[which can occur on the bitumen, with sustained heavy braking].
It is possible to get roller bearing greases with extremely high water tolerance/absorption capacity [these see wide use in [e.g.] paper mill bearings], but these are exy industrial products, only available in 20kg+ pack sizes...
I can recall one quite specialised grease of this type, used by Aust Paper's Maryvale mill, that cost over $3000 for a 180kg drum, over 20 years back now.
