Steering vibration help.

[justanotherhigh]

Okay, story of events: Volvo 240 DL, power steering.

2 Months ago - purchased car. Steering wheel vibration at 50-60mph. Front tyres don't look so clever. Think this is cause.
1 Month ago - swapped front wheels off GLE, no change.
1 Week ago - hear knocking from front passenger side. Find nothing but bearing play, adjust but reappears after 100 miles as before.
Swapped front hubs and struts from another 240. No change.
When car is on the ground, has play in both front wheels, feels like bearing play. Once jacked up, play disappears.
Suspect balljoints.
Yesterday - Replaced bottom balljoints with new.
No change.
Noticed when wiggling steering wheel left to right can hear slight knock - should I suspect steering rack? Can't find ANY play in trackrodends, wishbone bushes etc. It's confusing hell out of me at the moment, even took it to a garage and apparently they couldn't see anything obvious.

Just to clarify, it's definitely NOT tyres or wheels or brakes.
Car has been known to wander at speed though.
Any thoughts? Really scratching my head here.

[swampy76]

Does sound like play in the rack

Had similair on a 306

[taurus]

Check the suspension bushes. Play which disappears when it's got the weight off the wheels makes me think there's a worn bush that allows movement when the suspension is under load (ie its usual position).

[justanotherhigh]

I really don't know. The only thing thats left is wishbone bushes and i'm sure they are okay.
I did notice though... if i lightly wobble the steering wheel...which is easy enough.. there is no wheel movement... at least with the engine off... d'oh.