David, do you experience judder when manoeuvring the car? I think I know the issue, I had it on mine when I first got it. Has yours stood for a while until recently? If shockers are ok and its yes to standing then I suspect you are experiencing king pin striction at low speed and on bumps, caused by cross metal chemical corrosion whilst stood up and not used. The power steering masks the sticky steering I found, which is more evident on one without it. Mine had standard KP's and I changed to using Lucas Red n Sticky grease which stopped it and lasted much longer and is hydrophobic. I'd pump grease down the top nipple until fresh comes out the bottom, then pump the bottom one. Take the car out and Go up and down a rough section of road at a speed that will give the suspension a pounding. Then re-grease pumping all the old grease out and see if the Shudder has gone.
