having some issues with my 1994 850's front passenger side suspension - having just purchased the car I first noticed that the front tires have shown an unusual amount of wear characteristic of ball joint failure - the guy I bought it off of had the driver side ball joint replaced but there is still a lot of thumping noise from the passenger side when going over an uneven surface - upon inspection though the ball joint (and tie rod) appears to be fine and does not show excessive play when pryed - should I be looking at other parts of the suspension to correct this problem???

At that age, you probably need shocks and all of the rubber pieces between the wheels and the body.
ED7

I just corrected my 93 850 with a new set of outers and ball joints. My steering was tight but the rubber was split on the tie rod ends and ball joints. I would not have believed that replacing the ball joints would make that much difference in the handling.

Regards,

Strut bushings are a common thing to wear out and will cause a thumping when hitting a bump or pothole.

A worn out spring seat can do that. To check it, take a very large wrench and turn the bolt on top of the strut tower clockwise. If it turns easily, the spring seat needs to be replaced.

You will also need an alignment, but do that after you replace the struts and spring seats.

BTW, if you get new spring seats, get a pair for an XC90 - OEM, they fit and last forever.

Klaus
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Two great Volvos, a 1967 220 and a 1998 V70R