wandering steering

i have just bought a 1991 200tdi and i have the problem of feeling like im gonna be thrown off the road. nothing appears to have any play in it though i was told to change the a frame ball joint. would this cause the feeling of when you turn the steering wheel there is a delay in it working how you would expect it to. i have put one shot greece in the swivel pins in the hope this would help. im now at a loss as to what to try next. can the steering box be adjusted if so how do i do this.

The first thing to do is to check properly all the bushes, especially the panhard rod ones (my Disco used to eat them before I fitted poly bushes) now check all the track rod ends & ball joints, don't forget the one on the drop arm etc.
Then once you're happy with the bushes and joints, check the tyre pressures and get the tracking done.
If then it still wanders & you still have too much play in the steering, you may need to adjust the steering box. Basically you slacken the locknut and tighten the centre bolt a bit at a time until the slack has gone, but be careful not to tighten too tight. There is a good article on here somewhere with photo's etc and how to do it.

failing that-steering damper or swivel preload

If after all that...

it'll be the A-frame ball joint.

thanks for the advice think i may have a busy weekend under the old girl....

I suppose u dont have 18" wheels on it... cos if u have replace these with smaller(16") wheels before u do other things.... u'll be amazed about the difference

Do the lot. Especially swivel preload, they're a real swine for wild steering!