If you find the above mentioned spacer in the correct position, have a look at the push on end cap/spacer that goes on last at into the end of the hub (freehub end), this has a raised centre machined into it which contacts the inner (none moving) race of the outside bearing. This can wear/fret over time (see pic) to the point where the outer part of the spacer, when tightened under pressure, can touch the outer (moving) race of the bearing and the seal, causing at least drag, if not total seizure.
The difference between the inner and outer faces on this spacer is only 8 thousandths of an inch (0.2mm), and with it being alloy against a steel bearing, it can soon wear.
All is not lost though. A mate of mine had the same problem 18 mths ago, I stuck it in the lathe and re-machined the profile back to original ( minus about 10 thou ), its still going strong 😉