New Thrust Arms...NOW I have the shimmy!

[Mr Project]

Well, just replaced my thrust arms with Lemforder/750 units from BMA. I was getting the clunk under braking pretty badly, and some severe wandering. The new arms fixed those issues, but now I have the 50-60MPH shimmy! I didn't have it before, and I have receipts for front lower control arm replacement about 20k ago, supposedly.

I'm fairly certain that I have some slop in the steering, too. Just tightened the column nut, but there is still a little slop. Any possibility that this is shimmy-related?

[632 Regal]

any play in the front at all can cause shimmy.

[JustinM]

i just replaced the Upper and lower control arms and tie rods,alignment ,wheels balanced and now i have a shimmy...i'm having a shop look at it tomorrow and see if they can find anything wrong ....

[TETSUO]

yep just replaced my lower control arms, bushings, and back shocks. Got a mean shimmy now. It's going back to the mechanic next week though for some other stuff so maybe he can do something about it

[Mr Project]

Wow, guess I'm not the only one in this boat!

[steven]

i just replaced my upper arms/bushings, shocks all around, new tires and new disks in the front to end up with a crazy shake at about 60. all an alignment did was make the shake worse.

a good old wheel balancing made everything right again. i say start small and hit the cheap stuff first. where do you feel the shimmy? it could be beyond suspension (driveline stuff - guibo, center bearing, mounts etc).

[MicahO]

If the shimmy is consistent at speed and not induced by braking, it's likey wheel balance and not the new arms. You may have done something pretty simple when re-mounting the wheels. Try pulling the wheels back off and make sure that the mounting face on the brake rotors and the backside of the wheels are completely clean. Getting some grit in there when re-mounting is sometimes all it takes to induce a "wheel balance" shimmy. Cleaning up the mating surfaces may be all it takes to clean it up.

Same would go for the brake rotor mounting surfaces if you had them off.

[Mr Project]

Thanks, I'll pull the wheels and check this weekend. I did have a little anti-seize on the mating surface that I had put on before to prevent the wheels freezing to the hubs (had a dickens of a time the first time). Maybe I'll clean that off and double-check everything.

[MO525]

Thanks, I'll pull the wheels and check this weekend. I did have a little anti-seize on the mating surface that I had put on before to prevent the wheels freezing to the hubs (had a dickens of a time the first time). Maybe I'll clean that off and double-check everything.

I went and had the baboons at my favorite tire shop balance my tires AGAIN.
Well, they were spot-on BUT....
The dingbats didn't set the hubcentric rings on the WHEELS.
They put them on the discs...HARD...pushing them back to the point they weren't 100% in the wheel, as they should be.

I spent some quality time resetting the rings and cleaning the mating surfaces of the wheels and discs.
VOILA!
No more vibration!!!!!