First the near disaster. My wife and I just returned from a short road trip: seven days, 2000 kms, a hundred stops for one reason or another, all in a camperized Dodge Grand Caravan with automatic transmission. Last thing one does is to put the selector in Park and turn off the ignition. Day after we got back I took the Stanley out for a run. Got home, stopped in the carport, and started to put the automatic selector in Park, at the top of the quadrant. Car lept forward, and I managed to close the throttle and stand on the brakes, stopping about 2 cm short of the back wall.
Now the advice. I noticed a bit of oil on the floor under the overflow of the oil separator. I've never had it off, as the car doesn't use much oil, and the PO told me he'd cleaned it out. I took it apart, and I can't see how it's supposed to work. There are two major components: a large trap with a smaller collector underneath it. It's a Wright-Austin Type T. Here's a link to a website:
[www.steamdepot.com]

Obviously the large trap does it's job, as the small collector had a lot of sludge in it, but I can't find anything on the small collector on the internet. There's a cup that acts as a float, but the process is not clear to me. Anyone familiar with this set-up? THanks in advance.

It’s not an oil trap.
It’s a steam line trap, it would separate any water in the line. The cup is a float that traps air and lifts the drain valve draining the water when it gets high enough. It’s not an oil separator, but it will separate any solids as oil in the line. You will have to clean it occasionally.

Rolly

Thanks. Do I take down the large canister, or only the smaller one?

There made in several models. There should be a hole in the bottom that the drain pipe is piped to, or in your case a pipe plug. If it’s a plug, you should be able to remove it and push a small rod up and lift the valve and let it drain. Or your going to have to drop the bottom half of the unit and clean it out.

Rolly