Ok, as if this wasn't confusing enough. Let see what the Volvo Manual says about wheel bearing. Oops, shouldn't have done that. It seem that their are three castle nut and two different ways of installing the bearings depending on the type of nut. If you have a 12 or 20 slot castle nut you tighten to 41 ft/lbs. while rotating the wheel during the last stage of tightening. Then loosen nut a half-turn. Ensure outer bearing's inner race has not stuck. Tighten nut until it is only just possible to move axial washer radially with a screwdriver. Loosen nut about a half-hexagon so that split pin can be installed in the nearest hole. After installing and locking bearing, hub should rotate easily, but without any play.

The second method is for a 20 slot castle nut with integral washer. Tighten castle nut to 42 +/- 5 ft/lbs.. Rotate wheel during tightening. Afterwards loosen nut a half-turn. Ensure outer bearing's inner race have not stuck. Tighten to a torque of 1.1+/- 0.5 ft/lbs. (finger tight)(finger tight is what it say's in the manual) Then turn nut to nearest hole and insert split pin. Their are two places in spindle where split pin can be installed. After installing and locking bearing, hub should rotate easily, but without any play.

And I thought threads starting " What's the best oil" were fun,

Ron J