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There are a number of pneumatic or hydraulic conversions on YouTube.
Bought one yesterday and set it up. Going up, worked fine. But it wouldn’t go down.
Propped up the end so the pedal could go lower and it went down. That indicated a problem with the linkage. Somewhat common.
Moderate length story short, the arm for the linkage was on the inner hole and the 3rd hole of the ring. The nuts holding the bracket were loose on both ends. Drilled a 3rd (1/4”) hole and now it works like a champ.