Originally Posted by
mtnbke
Campagnolo hubs should mostly be considered disposable if they are cup/cone. The problem is while you can replace the loose ball bearings and the cone (outer race) the inner race becomes pitted and galled. This race damage translates to trashing new balls then through the ball wear to the cone right back to where you started.
Campagnolo sells replacement cups too.
The only bearing replacement issue would be with 1998 and older hubs using steel 10mm axles (12mm for the freehub), where the drive side cones have become unavailable; although the OP's bike is 2004.
Parts are fully available for over-size alloy axle cup-and-cone hubs, and after that transition the less expensive models used cartridge bearings.