Sporatic wheel shake

I had this issue a few years back and replacing the tc rod bushings (whiteline urethane) seemed to have slowed the problem, but its back now and worse. When going 100kph or or over, the steering wheel shakes rapidly, sometimes violently forcing me to slow to under 100. The annoying thing is that this doesn’t happen all the time… smooth road, rarely shakes - as soon as I hit a bump or dip, shake starts in intervals. Shakes for a second, stops, shakes for a second, stops. Its messed. And feels like it moves down the frame from front to back.

Ball joints seem ok, tc rod bushings are 2yrs old, tires are brand new & balanced (same shake with old tires, different rims), tie rods ok as far as I could tell. Shocks & springs are tight and look ok.

I’m at a loss at this point, any suggestions for what this might be? I’m afraid the shaking will start more problems if it persists.

95 240 LE

Thanks!
Jason

Alignment? Possibly your steering rack is crapping out and not keeping alignment…

I thought of that at first too… found a flat road to test it out and the car drove straight no problem.

I have lower profile tires on now so the shake is much more pronounced. Going over bumps sometimes seems to throw the front wheels around. Would any other bushings besides tc rods cause this?

Jason

strut top mounts?

put the up on a jack and shake the wheel left/right up/down without weight on it and then figure out what has play.

check your engine and tranny mounts.

i get the same thing in the winter if too much snow builds up and ices around my engine mounts. you should feel the vibrations intensify with increasing speed and typical engine mount shaking is noticeable at around 100 kph.

if you find that it is the mounts, i would recommend changing both engine and tranny mounts if you don’t know when they’ve last been replaced. g/l.

1)- similar problem (going over a bump) turned out to be 1 of the rear struts was shot -check it out by bouncing on the rear (and front) bumpers -there should be very little rebound -sometimes easier to check against another 240 that does not have this problem

  1. similar problem (occured more or less randomly)turned out to be unevenly worn rear brake pads --uneven from 1 side of the pad compared to the other side of the same pad -

Let us know what it turns out to be.

Thanks for the input guys!

kimmerkaze, I never thought about the mounts… would that still happen in the summer since there’s no buildup of crud?

john, i bounced all 4 corners and everything is tight and responsive. I recently did all 4 brakes so unfortunately that isn’t it.

A guy at work suggested the front swaybar bushings. Would this make sense? How could I check them without ripping it all apart?

yes. if the mounts for the engine are done, the whole car typically vibrates at higher speeds and in bad cases, the vibrations from the mounts can reach the steering rack, which would cause steering wheel flutter. you should also be able to feel the vibrations pretty noticeably in your ass while driving.

i would thoroughly check or get a mechanic to check your engine AND tranny mounts. if the problem’s bad enough, you should be able to feel your engine shaking pretty badly on start up. if this isn’t happening maybe check your tranny mounts but based off of your description i’m guessing it’s engine mounts and mayyyybee tranny mounts too. don’t invest a penny on parts until you fully inspect the mounts first though man.

john - i doubt there’s anything at all in the RR end that would cause steering wheel flutter.

further as per my last post

1 and 2 occurred on our own cars therfore no room for doubt…

  1. I have not experienced but heard from another member that a bad subframe nut/bolt/wornout bushing can cause similar problems

I’ll get those mounts checked out… Thanks everyone for your input!!

The guy that I work with that had a 97 240 w/SR mentioned the engine shook more than normal on start-up. I rarely feel the vibrations in the seat though, mostly from the steering wheel. Pretty much the only time that I feel it that bad is when I’m going over 100 around a tighter bend in the hwy… then it just feels like its flopping all over the place forcing me to slow down. The real pain of all of this is that it doesn’t happen 100% of the time. Sometimes it won’t do it at all.

Jason

Just wanted to post an update on this issue: I had the car at the shop and they checked the engine mounts. They said that the engine does rock side to side when starting and giving it gas but its not abnormal. 2 techs that were there said the engine would be moving up/down, fore/aft rather than side to side under the load they gave it if the mounts were toast - which it did not. They didn’t have time to check anything else when I was there and couldn’t suggest anything else at the time.

Jason

Another update from my recent visit to the shop for an oil change. Tie rods ok, ball joints ok, tc rods & bushings ok, alignment ok, tire balance ok, front sway bar bushings ok. Not sure where else to look… I’m feeling the shake more in the drivers seat than before - steering wheel still vibrates as it did before, quite annoying after a long drive.

Any more suggestions would be great!

Thanks all,
Jason

My 2000 impreza does this, much like yourself I have had all my balljoints, tie rods and Controll arm bushings inspected numerous times without anyone being able to find the play. I’ve had 2 different sets of rims on the car with new tires on both sets and all my brakes are new. I’m still not sure wtf is wrong.

If all your front suspension you listed off is actually in good working order, then theres really not much left that would cause vibrations… If your wheel bearings are bad enough i suppose that could do it.

I’ve never actually heard of this happening but it your rubber steering colum bushing is really bad that may do it also.

An out of balance drive shaft you would feel more through-out the car rather then the wheel, so thats all I got, if everything else checks out then this is all thats left i think…

It’s possible that your wheel is warped?

ok have you ever check the tires or rims. i know of many people that put their car into the curb and screwed the rims.

Also try another set of tires and rims. i have a 2005 savanna in the family an it was dong the same thing. After i put money into new tires, it disappeared.

So see if you can borrow some or if you have some to test with good.

Thanks for your input guys, here’s another monkey wrench for 'ya. At first I thought it was the tires or rims. I’ve had 3 sets of tires / rims on and it happens to all of them with varying amounts of shake due to the different tire sizes. It’s F’ed and driving me nuts since I do a lot of highway driving. Its like being Sherlock Holmes… trying to find whatever it is that’s loose.

Jason

its your rac and pinions
its a little bit loose mine does the same thing its not dangerous its just annoying as fuck although mine only shakes at 120 not before or after that speed

did you check the bushing on your control arm ??? had the same problem with my car when i first got it, turned out to be the control arm bushings… i just changed the both control arms w/ new ball joints just to be sure. or just buy those aftermarket bushings the you can use to replace your old ones
PDM sells them >>>> http://www.pdm-racing.com/products/pdmcontrolarms.html

Wow those control arm bushings (whiteline) are pricey! $142 a pair. Seems plausible that they’d be the cause. How much of a pain were they to replace? I’ll be sure to check them out!

Thanks,
Jason