All vanagon (except for syncro fronts) wheel bearings have two sets of bearings,
either ball and roller (rear), or a set of tapered roller.

In the case of the rear, only the ball bearing can resist lateral loading, the
roller bearing only locates the stub axel radially. If there is "play" in the
bearing it is because either the bearing is totally shot or the big nut is loose
and the bearing will soon be totally shot. With the whole thing torqued up there
should be no play and since only the ball bearing (alone) locates it laterally
temperature effects do not take place.

In the front there is a set of tappered rollers that oppose each other. When
adjusting the bearings ALL the play is taken out and then the nut is backed off
till the washer is just movable. At this point Play is just about 0. When the
hub & spindle heat up they make the respective parts longer in the axial
direction. If the spindle gets hotter then the hub it expands more and you get
some bearing play. If the hub gets hotter then you get less play and maybe some
preload, but thats why the bearing hub part of the front rotor is cast somewhat
remote from the heat producing brake surface.

But in both cases with the bearing properly assembled you should NOT have any
detectable play in the bearings. If you do find out why or else!