Manifold Hose Nipple removal

[L78steve]

None of the above has worked for me.What happens if there is corrosion is the aluminum transfers to the steel and when you unscrew the fitting it tears out the threads.The only thing that works is to drill a hole if its a plug.Then take a jigsaw and slowly and carefully cut from the drilled hole towards the thread stopping short of the alum.Then with a Vice Grip collapse the plug or fitting then unscrew.