okay-figured it out but thought I would post it in case anyone else had the same issue.

there was a cotter pin that was sticking out that had to be pulled and then the handle comes completely off. However, when we pulled on the piston, it still wouldn't pull all the way out. We used dishwashing liquid to lubricate the shaft and then pulled really hard.

replaced all the O rings, re-assembled and it works perfectly. No leaks!