Servicing a Zipp 303 free hub.

Haven't done one in a long time, but they are pretty standard hubs... 5 mm Allen Key jobs to remove the caps I think, then you pull out the culprit, give it a good clean, relube with grease and re-fit

webboo said:

Turns out you just tap the caps off. I used a quick release skewer from the other side. This and no preload adjustment makes them a bit sh*ty overall.

You can live without preload, there is a lot of load on the wheel and once it's there, side to side movement is prevented. I seem to remember the older hubs did have a preload cap, but maybe I am confusing them with some others... it's been a long time since I played with a Zipp hub

webboo said:

I have had the bearings and the free hub replaced. However you can still move the rim from side to side.

You can, but try leaning on the saddle and do the same, you'll find that you can't... and that's what happens when you are riding

webboo said:

I’m sure you are right but none of my other wheels have play in the bearings like the Zipp.

I had a Novatec 542 hub that was the same... never been a problem

Must be a lot of side to side play then... time for a tiny washer carefully placed in the right spot?

If you have play, it means the axle is allowed to move sideways, or in other words, the hub body is allowed to slide on the axle, when the latter is clamped at the ends in your dropouts. If you add a tiny washer at some point between the two hub caps, that won't happen anymore. Problem is where to place it and how thick it needs to be. Definitely a sub millimeter washer, maybe at the base of the freehub or between the freehub and the hub cap. One could start by trying a thin plumbing rubber washer with the inner hole the same size of the axle and see what happens. If it's too thick, you'll have a lot of friction, or no movement at all