I have had constant alignment problems with my Blazer. I recently bought new tires (Cooper Discoverer ATR) and have had it aligned and balanced. The new tires and alignment helped for about 1,000 miles, but then the alignment goes out. It seems that when the alignment is done, it is fine on rural roads, but not on the interstate. There is also a popping noise coming from the lower leveling arm on the left front, which I was told by the Chevrolet dealer it could use replacing. The guys at the alignment shop said they got the alignment perfect, but the steering wheel when placed in center position pulls to the left very noticeably (which they said they centered the steering box). Also very violent shaking of the dash and steering wheel occur between 70 and 80 mph on the interstate. What's the problem????

 

Sounds like you need a new alignment shop. You obviously have worn and/or broken components in the system that is causing your problems.

 

There is an adjustment cam on the upper control arms the tends to wear out over time. If this is your problem, there are two courses you can take. Replace the bolt and cam or next time you get an alignment have them tack the cam in place.

A good shop should have told you this.