I have a trick that has been around for a long time. This is a trick we used to use for exhaust manifolds when the bolts were so rusted in that breaking a bolt was very likely to happen. To avoid having to remove the stud in a separate process we used this trick to get them loose. This works better with a fair amount of heat to start and then let the wax slowly cool for about 3-4 minutes before attempting to remove the bolt of nut.