I have an old shower (see pictures) that leaks. I am going to repair some tile that I've removed, but before I do that I want to fix the leak. I've spent the past 3 days getting the handles and covers removed and cleaned (CLR) and polished with chrome polish. Then I tried to remove the stem, without luck. The stem nut comes out ok, but the stem will not budge. Is the something different in a shower stem as compared to a kitchen or bathroom sink stem??

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