steering intermittant stiffness

1992 disco on 100k. Can be fine for a few days, but then I'll get a few days, or miles or a single bend with the problem. seems more right hand than left hand bends though.

The problem: at any speed above stationary driving (or in neutral rolling) the steering seems to have a point of stiffness that needs to be 'broken through' to steer a bend. Mostly from straight to turn a curve in the road - bit like you have to lightly jank it through the problem - which i think is slowly getting worse.

what I've changed: I've replaced all (4) steering ball joints (track rod ends and drag link) and had the tracking checked. Steering did have a slight wandering to it, but that for the most part has deminished since changing the ball joints.

I've also got the lower UJ for the steering coloumn - in case.

I suspect its a sticking CV joint, but just after other thoughts. Steering fluid levels are good and can see no bubbles or anything when i steer.

Mine does exactly the same...

I have a split on ball joint on the steering box drop arm, if I grease this up and spray WD40 on my steering column shaft, the problem goes away..

I think I might have play on the steering column shaft UJs, have a spare one at home but havent got round to fit it yet...

I've replaced all the ball joints and the drop arm and drag link ball joint. I've also now just changed the lower UJ on the steering rod - steering wanders much less, but the steering occasional stiffness still there. the only remaining original parts in the steering chain is the steering box and cv joints. can't imagine it would be a swivel joint, but not ruling them out.