Manual Transmission - T56 master cyl. / line question

I have aused clutch master and line that I'm using to mock up the trans in the car I'm building. The line was disconnected from the master when I got it. When I reassemble it with a new roll pin it seems too loose ,like it's not tight enough too seal the o-ring. Here's a picture of what I have. Someone please tell me if I'm missing something.
Thanks

A clearer picture

Anyone ?

I think I read somewhere that there is some kind of black ring, other than the washer, that is suppose to be in there. When I took my M/C apart I didn't notice one, but I didn't try to pull anything out either.

There should be an oring in the MC as well as on the line..

Look here for pictures.

http://www.installuniversity.com/install_university/installu_pages/sophomore_year/drill_master_cylinder.htm

Thanks for the help. I put another o-ring in the body of the master ,it seems tighter now. We'll see if it seals in a little while.