Question is,how do we get to the first step when we have a grease nipple in the middle of the axle?
I'm no expert on this but from what I've picked up around here I think the answer to your question is "it depends". There are add on grease caps for some axles which have a grease fitting in the middle. There are also Bearing Buddies
which were originally designed for boat trailers but have been added to many trailer axles. My understanding is that these are helpful in getting grease to the outer bearings on an axle
but do nothing for the inner bearing and, as such, still require the normal procedure for repacking that inner bearing.
The other possibility is that you have an EZ Lube
axle which has a grease fitting that allows you to "pack" both bearings with a few squirts from a grease gun. When I ordered the new axle for my Boler
I made sure to spec an EZ Lube model since I've always hated doing the bearings.
Hope this is helpful,