Found the info on TIS mate so hope it helps.
Wheel Stud Replacement
Removal Procedure
1.Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle.
2.Remove the tyre and wheel assembly. Refer to Tyre and Wheel Removal and Installation.
3.Remove the wheel bearing/hub. Refer to Rear Wheel Bearing and Hub Replacement.
4.Release the wheel stud (1) from the bearing hub with the hydraulic press and DISCARD the stud.
Installation Procedure
1.Install a NEW stud into the bearing/hub assembly (2). Add enough washers (3) in order to draw the stud into the hub.
2.Install and tighten a wheel nut (1) until the head of the wheel stud is fully seated against the back of the bearing/hub flange (2).
3.Remove the wheel nut (1) and the washers (3).
4.Install the wheel bearing/hub (2). Refer to Rear Wheel Bearing and Hub Replacement .
5.Install the tyre and wheel assembly. Refer to Tyre and Wheel Removal and Installation .
6.Lower the vehicle.
Printable .PDF below for you.
http://vxoc.org.uk/Images/vxoc%20astra-j...cement.pdf
Astra-J 2.0 CDTI S/S
Retrofitted AFL, TPMS, Navi950, BT, DAB, Rear Camera, Infinity sound system, Towbar, Flexfloor & more.
I can do programming and retrofits using genuine GM MDI and Dealer software.