[qcj]

I need a little help in rebuilding the dump air cylinder. As you can see in photo one I have it apart and I can see another snap ring at the bottom. The black plastic part must come off somehow so I can get to the two other 2. How does this bottom plastic part come off? I looks like it might be screwed on but when I turn it the part inside turns also. Once I get this off I'm home free. All help appreciated.