Discovery 2 steering

Hi guys can anyone offer me any information so I’m experiencing some very vague steering at 70 hard to keep in a straight line I have checked the track rod ends and the ball joints were replaced in March I did adjust the steering box in March and since then the steering doesn’t return to centre there is no play in the steering the best way to explain it is only takes abit of a turn and it seems like a lot it is dangerous between 65 - 70mph I haven’t tried to go any faster is it possible that the steering box is to tight or could there be another problem I brought a new steering damper a while ago and that made no difference any help would be appreciated also when at 70 the steering is really light and is stiff at a slower speed.

Have you checked the tracking?
Excess toe out can create a very twitchy feeling / too responsive

Easy stuff To check...
tire pressure?
When was last time each each wheel was balanced?
Check/flush power steering (ps) fluid?
screen at bottom of ps reservoir clogged up?
Any leaks at steering box?
All steering linkages hardware tight and not loose?

I have read a few guides on steering issues i don't consider myself an expert by any means but from what I have read if your steering doesn't return to centre on its own then you've gone to far with tightening it. When you adjusted it did you turn it from 1 full lock to the other feeling for any tight spots? Tight spots also an indication that its been over tightened. I've had vague steering for a while and adjusting the steering box did improve things but for me changing the front bearings made a huge difference. I'm not sure if it would be the same on your disco as mine is a d1 but it feels steady now. Had that not solved the problem I was going to look at for play in the shaft before the box. Play in the pitman arm and play in the panhard rod. Good luck with tracking it down.

when I replaced my Drag link and Tie bar my steering, went from very vague to a positive no steering wheel play in an instant, and I would recommend changing them out to get good positive steering