Regards the HGV Trailor, them studs are Splined at the rear so they do not come loose, Back to your Question, First of all get your replacement studs & nuts, Take the Hub off by backing the brake off, then removing the lock nut & Split Pin remove the hub, Use an Angle Grinder to remove the Stud either within the rear of the hub or the outside, Do not use a Chisle or large hammer as you have every chane of cracking the Cask Iron Hub.
Trebor, February 2008