Hi, I have a 2 1/4 ton floor jack. Made by Shinn-Fu Model G-818 Lift range 5 1/2 to 19 1/2 inch range. Has been a great jack but just failed last week when I tried to lift a box trailer. Pump it up and it just returns down slowly. No external leaks. Does not owe me anything as I have had it many years but would like to rebuild it if possible. I see I can get a rebuilding kit for it. I took the jack apart and have the ram itself in a big vise. I want to unscrew the large cap on top of the ram. It will not budge. using a big pipe wrench with a cheater bar. No go. Any suggestions as to how to remove the top? Thanks.
