Control Issue Over Bumps
 

My '09 Sonata GLS is unstable when I hit bumps at above 60 Kph. The tires would feel like they were bouncing excessively when hitting bumps even below 60 Kph. I got the 2 front struts assemblies, front links, rear shocks and rear latitude control arms changed this week. The bouncing is a lot better, but not perfect although I used cheap parts given the car is 10 years old. The problem is that the rear still feels like it's bouncing sideways when I hit those bumps while driving above 60 Kph.

I asked the mechanic to check for other possible problems with the suspension while he was replacing my other parts and he said everything else was good. I researched the sway bar to see if that could be the problem but from what I gathered, unless it is broken, worned rubber bushings would cause a knocking rather than a sideway movement like I am sensing. So I'm out of ideas.

Have you thought of slowing down and avoiding the bumps???
If you can not avoid them then at least slow down???

It is an old car.
The only thing left is tires and rims

Define cheap parts? I went cheap on struts once and although they were "ok" definitely lacked refinement and much control. I stick to wel known brands usualy like KYB, Monroe, Gabriel etc.

I bought them from AutoShack (Prime Choice). I forget their in-house name brand but they are cheap China-made parts. Like I said, I don't think there's anything wrong with the new parts as the car handles the imperfections of the roads much better then before, although I'm sure better quality parts would have given me a smoother ride. My main concern now is that the feeling that the back end is bouncing sideways when I encounter some bumps on the road has me worried that something else is wrong with the rear suspension.