78 series landcruiser problems steering out of balance wobble

Check steering & suspension joints if ok check tyres for distortion & wheel balance

Brake components may b worn. Inspect rotors and pads. So with the steering...git an xperiencd mech to testdrive

I have dismantled the steering rack completely in place and removed the casing by pulling it out.

Improperly balanced wheels can cause the wheels to wobble at speed which can be felt through the steering wheel. A local tyre shop can test the wheels for balance and make the necessary adjustments to the wheels by adding weights to even out the balance.

Defective rack and pinion steering gear.

its usually a tire balance issue at that speed. also check the front tires for seperation...it ussually appears as a belt break internally in the tire and can be found out by rotating the tire while you have it jacked up off the ground and watch it while its turning by hand

First off, steering wobble usually starts threw front hubs so ya best is first jack the front up so wheels are off the ground, hold the tyre top and bottoms an try to push it in and out, if there is play there than you may need to
Simply replace wheel bearings etc or in my case just repack and set em an Make sure you do the inner bit 28mm nuts up firm,

Second option is get a high quality steering damper which also helps heaps when 4x4 ing,

Third option could very well be play on the tirod ends an this can be checked by havin te wheels off te ground as steering lock off and just gentler trying to twist the wheel side to side an if there is play than u will know that the slak is coming threw the rod ends before friction hits the steerin arms hence causing vibrations

What you have is called death wobble. begin with properly balanced tires. Generally the most frequent cause of the wobble is a bad ball joint,(check first) track bar bushing or elongated track bar mount hole. It can also be caused by steering box becoming loose on the chassis or a combination of slightly loose steering components, any of which alone would not matter. The steering damper (sideways shock on steering linkage) is often blamed for the wobble. It can be damaged by the wobble but it will not cause it. Replacing it may eliminate the problem for a week or so but it will return as soon as the damper fails again.

I would start by first making sure you dont have a bent rim. Check the tires for any bubbles in the sidewall or any deformation in the tire as this would suggest a broken cord inside the tire. If that checks out, get the tires balanced and see if that solves the problem.

Check your tires for abnormal wear, out of balance, maybe alloy rim out of roundness.