I spent last weekend replacing the front steering an suspension. I had what felt like a lot of play in the steering wheel and, more recently, a worsening shimmy in the front end at around 30 - 40 mph.

I replaced tie rods, idler arm, control bar for steering. Struts, strut tower braces, ball joints, and springs for the suspension.

Took it in to a shop for a front end alignment after I was done.

Today, I took it onto the highway for the first time and noticed a shimmy in the front end. I exited the highway and it became much more noticeable under 20 mph. The whole front of the car shakes left and right a little bit, but I don't really feel it in the steering wheel. This is very different from the shimmy I was trying to fix - the 30 - 40 mph one.

I'm assuming I must've done something to cause this. Any ideas what? Something stupid and obvious? Or subtle yet common?

 

I went back and checked all the bolts for tightness, and found the issue. The strut mount!

When I did the work, I went over every bolt, tightening to torque specifications in the Pontiac service manual. But the manual didn't have an entry for the strut mount. It was also up on top of the car, not under, where I was doing most of the work. So I missed torquing those down. Once I tightened those up, the shimmy disappeared.

 

Lucky for you!!

Those shimmy's can be like looking for a needle in a hay stack

 

If you took it in for an alignment, they should have noticed that. They move the mounts for the alignment..

 

sounds like a bad alignment ...... what 86IROC/Z said . good luck ...