W124 Intermittent Nervous on-center steering

1987 300E. Recently replaced one tie-rod end and idler arm bushing. All new control arms in the rear. New 205/55/16 Yokohama W rated tires. Alignment adjusted and then verified by a second shop.
The problem is that sometimes the steering feels nervous and unstable in the center position. It feels as if the front end is in a constant, if subtle, change of direction from one side to the other. I would describe it as if the front wheels are minutely changing direction on their own and that something is loose in the connection between the steering wheel and the wheels. It is very distracting to me though someone else might not even be bothered by it. There is approximately 1" of play in the wheel at the center position.
The interesting thing is that the car is not actually constantly changing direction since with hands off the wheel on a flat surface it tracks straight as an arrow. The steering will follow the crown of the road but less so than my other cars. However, the steering does seem to be more effected by road abnormalities than other cars with more pulling on bad roads than I am used to. The other thing is that this symptom sometimes goes away for weeks at a time only to reappear with no apparent cause.
I would appreciate any thoughts about where to start looking. Thanks.
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Squirrly is what I call this. I own a '97 E320 and it had exactly this subtle steering behavior.
IMHO the tires on both our cars are too large and magnify such problems. OK, here's why.
I found that the front wheels' toe in/out caused the squirrly steering. As one drives on a local street, say at 25 mph, the car seems to favor first one side then the other. IMHO this is caused by rises and dips in the road acting on first one wheel then the other. If the front toe-in or toe-out exceeds specification the car will self steer because the wheels lack parallelism. Visualize too much toe-in - the leading edges of the front wheels closer together than their rear edges (spec. is about 1/8") - and a rise in the roadway on one side only, the wheel that now must go up will steer the car in its direction vs. the direction the other, now less loaded, wheel is pointed.
I check the front alignment thus: Exactly center the steering wheel and drive into the garage or other flat surface stopping the car with the parking brake. The steering wheel is dead center so each front wheel also should be too. The body overhangs the wheels so one needs to use spacers to compare the front to the rear wheel. I hold a 2" wide bubble level as a shim (not for its bubble but for its consistent width) on the front alloy wheel and sight down to the rear wheel against which I placed a Chevron Techron plastic bottle (not that that's special but it gives a 2.5" space from the wheel). Using this simple method I've found one wheel was toed out and caused the squirrly steering. One can correctly calculate the exact width of the rear spacer using high school geometry, adding the front spacer's width and adjusting for the car's front vs. rear track widths. But for a quick check these figures will suffice.
Hope this solves the problem.
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Well, the thing is that this seems to come and go. A couple of other things I have noticed is that the steering feels more stable when hard accelerating or pushing hard through a corner. If I hold the wheel tight straight ahead and resist correcting, the car goe straight for a short distance before following the crown of the road to the right. Also, I have had three alignments and replaced all 4 tires to try to solve this.
I can't say enough good things about these Yokohama AVS ES100 tires. Quiet, smooth and stick like glue.
The roads I drive on are generally pretty crappy. They are all crowned and I am constantly fighting a pull to the right in all my cars. This Benz is actually better about it than my other cars.

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Well, do the exercise that I outlined - its free and doesn't take long to do. I sight down the shim held against the front alloy's bead hump, not the edge where the wheel weights get clamped on to the Techron bottle placed against the rear wheel. My goal is to visually bisect the Techron bottle. That proves the front toe-in is correct for THAT side, then I check the other front wheel.
Your comment about hard acceleration suggests possible rear axle drift when it not under hard acceleration. I recall you had some work done there, perhaps that should be checked as an alignment shop checks a car that's essentially parked on the rack.
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Kappy wrote:

Those tyres sound quite exotic. Is it possible that they are unidirectional and are on the wrong way round?
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I have same chassis as yours with same size tire... Avon Tech M500. I do not have free play on steering wheel but I know my idler arm bushings are shot!
When I had stock Michelin 195-60R15 with stock wheel, talk about squirrelling!!!! AUGH!!! My car goes everywhere it wants to go on highway... constantly readjusting the steering.
I upgraded my wheels to the W211 style... OE Mercedes and new Avon 16" tires.. What a difference! It tracked straight and sticks like a gum. Yet, I still didn't change the idler arm bushing yet... I don't feel squirrelling anymore. But before I got my car, the previous owner changed all the shocks and also changed the front lower arms... so this might be your case... bushings on lower control arm is bad. Other thing to check is your sway bar linkage on all 4 corners.
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usually this is a very slight alignment issue. The front wheels might be ever so slightly towing out, so that the straight ahead position is on the verge of turning.
I know you said that you have already had the car aligned and checked, but still...
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These symptoms sounds EXACTLY like the problem that I had recently.
I checked everything on the suspension and steering and found the following:
Wheel alignment - OK Control arms, ball joints, bushings, steering parts, etc. - OK. A front coil spring was broken at its lower end. Front sway bar (stabilizer bar) was worn (in the area under the bushings the metal bar was thinner), and the rubber of the bushings was aged. This resulted in too much free play of the sway bar.
First, the sway bar and the four rubber bushings were replaced by new parts. And this actually solved completely the problem with the wheel wobbling.
The replacement of the both front coil springs after that was without noticeable effect.

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"" wrote: > 1987 300E. Recently replaced one tie-rod end and idler arm > bushing. > All new control arms in the rear. New 205/55/16 Yokohama W > rated tires. > Alignment adjusted and then verified by a second shop. > > The problem is that sometimes the steering feels nervous and > unstable in > the center position. It feels as if the front end is in a > constant, if > subtle, change of direction from one side to the other. I > would > describe it as if the front wheels are minutely changing > direction on > their own and that something is loose in the connection > between the > steering wheel and the wheels. It is very distracting to me > though > someone else might not even be bothered by it. There is > approximately > 1" of play in the wheel at the center position. > > The interesting thing is that the car is not actually > constantly > changing direction since with hands off the wheel on a flat > surface it > tracks straight as an arrow. The steering will follow the > crown of the > road but less so than my other cars. However, the steering > does seem to > be more effected by road abnormalities than other cars with > more pulling > on bad roads than I am used to. The other thing is that this > symptom > sometimes goes away for weeks at a time only to reappear with > no > apparent cause. > > I would appreciate any thoughts about where to start looking. > Thanks.
Hi there
I experienced this with a 300CE. It was actually preceeded by some creaking at the front end and which I took to be the front springs. The creaking stopped but the centre line giddiness got worse and of course I found out the problem and which is a common W124 weak point when I drove over a sleeping policeman or ramp at low speed and the lower ball joint pulled apart throwing the entire suspension strut assy out to one side and grounding the car. These are a sealed for life item and Merc do not give a fixed replacement interval rather a service check interval. The problem though is that because of the construction and the way the springe loads the whole assembly, any play in the ball joint is not easile checked on a ramp with Pry bars or levers. The only succesful way is the compress and unload the spring with clamps. At this stage any noise or giddines from the front end I replace them, they are only about $20.00 each.
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