Make sure you have good acceess to the joint e.g. remove the brake backplate etc.When you have got pressure on the joint try hitting the steering arm with two hammers at points 180' apart i.e. opposite each other. Sometimes with a tapered pin that works if you get the hits timed to be exactly together.. It sort of 'springs' the joint apart. Alternatively tap the splitter on the top of the pushing pin. Heat usually works though.