Got what I consider a good deal on a 79 300TD. Especially considering recent prices for these, I would say I got lucky. Still, you get what you pay for and there is MUCH to be done.

Mechanically it seems to run very well. Put in some BioD and hope to flush out some gunk. It's only had 2 owners before me, so that was a positive. Still there are some mechanical things that should be done (but aren't urgent problems), such as addressing-
upgrade fuel lines, filter
get the horn working
recharge the ac
vacuum for the door locks isn't functioning
front window needs a new seal
and a slight pull to the right
antenna motor

These all seem like reasonable issues that can be resolved quickly. Or am I wrong?

There is also some rust, but not in the frame, jack points, or floor. The rust is bubbly under the paint beneath the front window, in one spot along the side trim, and beneath the rear window there is a small hole (just under the seal). The car was painted a few years back, not a great paint job. But will that hold the rust from progressing? Or should I patch the hole, and fix the other spots soon? I am in Los Angeles, and it likely wont rain for 10 months, so..

Other things are mostly interior/cosmetic. It's kind of a mess. Needs work on DS seat, rear carpeting is done, all the carpeting could use a deep cleaning, headliner someday could be replaced.

Going to take it to Mr. MB Monday to have a good once over and take care of some of those mechanical issues. Hopefully nothing else comes up! But, what about this rust thing? Any urgency in that?

Oh yeah, it has the Becker cassette radio. So nice - but the cassette player doesn't work!