Appleseed
Appleseed MegaDork
9/15/21 10:21 a.m.

Pulled the front wheels of the Focus wagon to check on strut bolts after I replaced them.  I found the top strut rod was loose. Putting the tires back on, theres now a very noticeable shimmy in the wheel above 40mph. Figure some rust or crud got behind the wheel knocking it out of round. The rotors are only 2 weeks old. I made sure the hubs were clean, and there was no shimmy upon reassembly. The shimmy showed up only after the strut check.

So it has to do something with the wheels right? Pull the wheels and wire wheel the crap out of the rotor mounting area and the wheel center. 

Shimmy remains. Checked the lugs and they are tight.  A remote possibility is crap tires. Kelly super wonder milage saver cheapos. Never really liked them. Tread separation? 

I need some vectors.

 

John Welsh
John Welsh Mod Squad
9/15/21 10:40 a.m.

Are you running aftermarket wheels that are not hubcentric?  If yes, my guess is the lug nuts are tight but just because they are tight they could be so tight that they keep the wheel "non-centered" on the hub.  

Appleseed
Appleseed MegaDork
9/15/21 10:57 a.m.

Stock Focus 16" five spokes. Might pull the wheels and reseat them. Worst that happens is the shimmy remains .

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) MegaDork
9/15/21 2:56 p.m.

Look for fresh shadows on the lip.  Possible when you were manhandling the wheels you pulled a balance weight off?

jgrewe
jgrewe HalfDork
9/15/21 3:29 p.m.

I'd swap fronts to rears and see if the problem follows a wheel.

L5wolvesf
L5wolvesf HalfDork
9/15/21 3:50 p.m.
Appleseed said:

I found the top strut rod was loose.

The rotors are only 2 weeks old. I made sure the hubs were clean, and there was no shimmy upon reassembly. The shimmy showed up only after the strut check.

Did you figure out why top strut rod was loose?

Are the rotors the only thing you changed?

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
9/15/21 5:03 p.m.

Rotate the wheels one lug nut forward on the hub, one wheel at a time.

I mean, it does sound like you have a tire out of round, but if it was okay before, then there must be a place where things cancel each other out.

Appleseed
Appleseed MegaDork
9/15/21 6:52 p.m.

To clarify,  the struts and rotors were the cause of wheel removal,  not the shake. Initially, everything was tip top.  Once I removed the wheels to check the tightness of everything, that's when the shake started. Nothing else effected the car. Once I buttoned everything back together is when the shake started, and it didn't improve when I took the wheels off to clean the mounting surfaces. 

Literally, everything is fine, remove wheels, replace wheels, immediate shakes. 

I'm hoping there isn't something esle that let go, like a bushing or bearing, and I'm so focused on wheels I'm overlooking it.

 

93gsxturbo
93gsxturbo UltraDork
9/15/21 7:08 p.m.

Shakes constantly or under braking only?

Shaking constantly, increasing at speed but going away or reducing at certain speeds is likely balance issue.  Ditto on the statement about wheel weights, or move the wheels front to back.  Did you swap them left to right during the work, intentionally or no?

 

Appleseed
Appleseed MegaDork
9/15/21 7:25 p.m.

No swapping. Wheels went back in exactly  the same place. But I will look for missing weights. Shake is noticeable almost immediately and increases up to 50ish. Above that it seems to smooth out, but that's probably due to resonance.

z31maniac
z31maniac MegaDork
9/15/21 9:50 p.m.

If it was a BMW my first answer would be, Control Arm Bushings. 

Appleseed
Appleseed MegaDork
9/15/21 9:54 p.m.

In reply to z31maniac :

I'd agree with any/all those possibilities, if not for the fact the car was perfectly smooth right before I pulled the wheels.  

Antihero (Forum Supporter)
Antihero (Forum Supporter) UberDork
9/15/21 10:22 p.m.

Another vote for weights being missing/hit off/dropped/abducted by aliens.

L5wolvesf
L5wolvesf HalfDork
9/15/21 11:15 p.m.
Appleseed said:

In reply to z31maniac :

I'd agree with any/all those possibilities, if not for the fact the car was perfectly smooth right before I pulled the wheels.  

It may have been smooth but it was not 'right" because - "I found the top strut rod was loose."

KyAllroad
KyAllroad UltimaDork
9/16/21 6:43 a.m.

Put it up on jackstands and accelerate the driving wheels up to a modest speed and see what is going on.

Or take it to a shop where they can check your wheel balance...if balance is ok, check the wheel spin while it's on the lift.

outasite
outasite HalfDork
9/16/21 7:39 a.m.

Easy button: jack up front of car or one front wheel at a time, check tire and wheel runout using a jack stand sitting next to tire with a screw driver not quite against tire or wheel. Rotate wheel/tire assembly and note variation in lateral movement.

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