Mine were in for 20 years and I tried everything and couldn't get them to budge. Took the lower end to a machine shop he had no luck until he let us in on an actient Chinese secret that worked wonders!!! Just heated up the studs and case around and melted a bit of birthday candle on each stud let it run down between the threads and then did the double nut and they came out with ease! I was amazed!!! I used the same method on my next motor and it worked again