Here are some pictures from my trim repair, I hope this will help others to understand at least part of the mechanicals. If you have an understanding of hydraulics, it's a pretty basic little pump. If not, I would hire someone.
Something that is very note worthy, knowing what to ask for, is half the battle.
There are a couple small springs that go behind the needle valves, not shown.
Shown one badly worn needle valve that allowed pressure to bleed off.
Good luck