Weird issue suspension/steering

[VZSV857]

Looking to see if anyone can help. VZ SV8, shudder through steering wheel only when turning even just slightly, more noticeable at freeway speeds. Was more pronounced turning right than left and only a slight turn will induce the shudder. Suspected tyres so spun them all up and they are true, swapped front to rear to be sure and no change. Replaced front struts as one was leaking no change. Fitted new front castor rod bushes as there was a lot of movement in them and it improved heaps and is now worse on the left hand side. Kinda lost now as to the cause? Why would the issue swap sides? Doesnt shudder if turning lock to lock while stationary. Everything else appears tight suspension/steering wise.

 

[Fu Manchu]

Tie rod ends? Ball joints? Sway bar link?

 

[VZSV857]

Tie rod ends? Ball joints? Sway bar link?

All tight no play

 

[vc commodore]

Rack or power steer pump will be the cause...My bet would be rack though

 

[VZSV857]

Rack or power steer pump will be the cause...My bet would be rack though

I was thinking rack but doesnt explain why the issue swapped sides with new castor bushes

 

[vc commodore]

Have you checked the strut bearing plates? Possible one of those is failing causing it to bind up....Binding up can cause tightness with the steering

 

[Fu Manchu]

Once you replaced the radius rod bushes, you would have tightened up the front a bit, but what ever is loose or moving would have shifted its effects to the next weakest point. The front is now far less forgiving so that is referring the vibration to another point. That in turn indicates to me a common source across both sides. The steering rack and sway bar are the only two components that do that. Check the torque on the K-frame bolts.

 

[Fu Manchu]

There is a simple bush on the steering rack that might be jiggered.

 

[VZSV857]

UPDATE: replaced both control arms so new bushes and ball joint, now faults even worse but going straight. FML.

 

[VZSV857]

There is a simple bush on the steering rack that might be jiggered.

Is that internal?