820 steering wobble

[Erik OK]

I have a 1970 820 that has a steering wobble at high speed but only on hard surface. The ball joints in the front have some wear but the drag link and the drop arm move back and forth quite a bit. I popped the cover plant and checked the drop arm bolt that holds the arm on the tapered shaft and it is tight and the key is in the keyway. There is some play in the wheel, you can turn it some before the front tires start to move, is there a gear that could be worn or is it a hydrostatic system?

 

[Tx Jim]

Are the bushings/brgs loose on the bell crank that tie rods attach to in the center of frt axle?

 

[Erik OK]

The bushings have a little wear but my main concern is the the
drag link moves front to back a lot, maybe 2" and it causes a
severe wobble, I have to slow down to an idle to get it to stop,
if I'm traveling on a paved road if I put the right front tire in the
grass I can travel at road speed but if both tires on pavement it
does it bad. I looked at the parts breakdown but I'm not sure
what moves the drag link, is it a mechanical set up or strictly
hydraulic?

 

[Tx Jim]

Mechanical with hyd assist.