Aivars,

It sounds like the "weak link" in this particular car will be body rust. This body style has always been a little touchy about getting rust, especially in "salty" climates (snow+road salt). The body trim catches water and mud and salt in certain places and rust starts to grow. If the floorpans were replaced, it's probably because they rusted out. If you're lucky, the "surface rust" will really be just surface rust which could probably be controlled with a little TLC. If you're unlucky, it might be rust bubbles that start under the paint, eat all the way through the metal, and can only be repaired by a "surgical" procedure such as cutting out the infected spots and welding in new metal.

Other than that, I can't really think of a particular weak spot on these cars. The rubber components in the vacuum system start to fall apart after about 20 years, but if the vacuum system still work (door locks, engine shut-off, transmission shifting, EGR) it's likely that the previous owner already repaired them.

The auto transmission will shift a little stiffly if it's working properly. It starts in 2nd gear unless you stomp on it from the line.

170,000 miles is not much for a '77 model year. I'd say your best bet is to take a look at the normal wear indicators for a car, take a look at the condition of the the "visible" parts of the car, and make an educated decision about whether the previous owners took care of it. You know, check the oil, kick the tires, pull the cylinder head and give the pistons a quick visual.. okay, maybe not that last one.

If the body indeed does have only "surface rust," the interior looks well-cared-for, all the gadgets work properly, the vacuum system works, and the transmission shifts a little crisply (some say harshly) when it's reasonably likely that it's been well-maintained.

On the other hand, if it's rusted to pieces, the interior is shot, none of the vacuum components work, and the tranny feels sluggish or spongy, then IMO it's pretty likely that the engine, suspension, and drivetrain were also neglected.

Good luck and let us know how it looks and drives once you see it.

- Nathan
'83 240D "Steiner"
'00 New Beetle TDI