Hyundai Repair: hyundai elantra, hyundai elantra, wheels and tires

Question
I have recently bought a 2002, Hyundai Elantra (61K miles). Because the steering wheel was vibrating I went to a service-shop to balance the  tires. Unfortunately that did not solve the problem. Because the car was pulling to the right on a straight line too, I went to an auto-shop to do the alignment. It did not solve the "pulling to the right problem". I went back to the dealer and he changed all the wheels and tires (they are not new but they do not look very used). After this operation the car is now pulling to the left and the steering wheel is still vibrating. Please help!

Answer
Since you've installed used wheels and tires, the first place to look would be the installed parts.  

Wheel balance is the usual cause of vibration issues.  If the wheels/tires that were installed were not balanced at the time of installation, you should have that done.  If so, then you should check the wheels and tires for being out of round or bent.  If all that is okay, you should check the suspension for wear or collision damage.

The number one cause of pulling is what is called radial tire pull.  It simply means one tire has a different rolling resistance than another.  Swap your front tires and see if the pull goes away or changes to the other side.  If it does, you've found the problem.  Typically, you'll want the front tires to be matched to keep pulling to a minimum.