"Like all new cars, COBRA-trailer uses compact bearings since they
are
available.With this bearings, there is no repacking, greasing or
adjusting needed or possible. This bearings are sealed and greased
for
lifetime.
When you open the grease cap on the axle, you will see a self
securing
all- metal nut ( Without any safety pin)

On older axles there is a crown-style nut and a safety pin through
the
nut and the axle stump. This bearings need to be repacked, greased
and
adjusted."

This is per Cobra/AS
Mark Mahan
2K