My 1989 240 (160k miles) has some suspension issues that the dealers have not been able to properly diagnose. It is now at a family Volvo mechanic a few states away where he plans to make it go away for good. I would like to pass on any info that might help him.

The issue is shaking and vibrating at highway speeds (primarily the front-right) as well as loud creeking over potholes or speed bumps. (The ride is very rough compared to the 1989 240 loaner car I am currently driving). The ball joints were both replaced 2 years ago, then just last month the dealer found the front-right ball joint very loose again and replaced it (as well as a tire balance and alignment).

So far, while looking under the car with the family mechanic he pointed out a rusted through front-left lower control arm which he is going to replace with a junkyard replacement. Also, while looking at the front of the car on the lift, my father in law pointed out that the front-right wheel looked like it was hanging crooked a bit.

Any specific areas I should ask the mechanic to look at?