Mercury Tilt trim leak

[Myfirst boat]

Hi I'm new to boating and forums. I have a late 80s mercury 35hp with power tilt/trim. I have a leak from the middle piston around the shaft. I purchased a o-ring kit and and have been feeling my way disassembling the piston. After many hours I have the piston assembly out and I'm now stuck on how to remove the "check valve assembly" at the end of the piston so I can slide off the end cap to replace the o-ring and scraper washer. It had 2 hole for a spanner wrench but don't know if it should twist off?? Should I apply heat?? Any help would be appreciated!!!