Picasso 1.6hdi 2009 Front Hub Nut & Rear Hub Nut Size & Torque

Hi all,
I have offered to change rear discs and CV joint boot for a friend.
He has a 2009 Citroen C3 Picasso
Do any of you fine folk no what size sockets I will need? I don't have any very big sockets so I'm certain I will need to order them.
Also, what torque should these be tightened to? I have a big ol' torque wrench that goes up to 500nm... any more than that and he can forget it!
Thanks in advance,
Ash

Hi, I've completed the job mentioned in the first post. It may be worth noting that this car has a VTR+ trim level.

The front hub nut needs a 26mm socket and should be tightened to 312Nm (Citroen and a few forums say this).

The back disc retaining nut is also a 26 mm socket and should be tightened to the disc/bearing manufacturer specification. The specification from the bearing/disc manufacturer trumps anything from Citroen or elsewhere as the bearing is the important thing to be torqued correctly. I used delphi discs with bearings but they didn't specify a torque.

I couldn't get any consistent advice on the torque for the back disc retaining nut so this is how I worked it out. The nut is one of those types where you hammer a dent in it with a chisel where there is a notch in the shaft to stop it coming undone. I slackened the nut enough just so it turned freely but I didn't take the nut off completely. I started at a low torque and tried to get the damaged section of the nut to line up perfectly with the notch out of the shaft. If it clicked too early I increased the torque. I repeated this process until I got the click just as the squashed section of nut lined perfectly back up with the notch out of the shaft. This was at 250Nm. Make of that what you will but I am very happy with it.

Happy mechanicing folks...