There ain't much inside a calcutta 400A or B.
This link gives you an idea (although I disagree with the need to change the washers, he uses WAY too much drag grease on the washers he puts in....t the regular ones only need a very thin film....and the corrosion block in the bearings seems strange to me.....I use rocket fuel yellow (or red in the TEs used with big plugs). Of course the guy fixes reels for a living so maybe I'm wack instead.
calcutta 400a
There are also links for the TE although that reel is a bitch to get all the way down.
ReelSchematic - Shimano Calcutta TE Maintenance
Threaded Mode