My 87 300TD had a strage wandering problem, as far as i know nothing had recently been done to the front end or suspention(only had the car for 2 weeks).

Used the search and found a simple fix to try.

Jack up the front end so that both wheels have no weight on them then put the key in the ignition and release the stearing lock.
Grab the tire and try to make the steering wheel move. You should be able to move it without to much trouble. If you can't move it you have a dry ball joint.

Look for the ball joint that has some rust around the clip, this will be the worst one. Both of mine where try. Pry the clip from the bottom of the ball joint and spray your favorite lube in.

My problem went away after lubing both joints. The ball joints will soon need replacing unless i can get a grease fitting in the bottom, i'll try that tomorrow maybe.

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82 Rabbit diesel (first d), 84 Jetta turbo d (300k when sold), 83 240d (305k when sold), 84 F250 6.9d w/Banks turbo(parts truck), 86 F250 6 cyl.gasser(waiting for 6.9d), 84 300d ( 347k Sold 8/04), Y2k New Bettle TDI (185k miles), 95 740IL (wifes), 87 300TD (206k Sold 7/05), 05 Passat TDI Wagon