W221 steering wheel wobble/shimmer/shake

[pembssurf]

I had a Mercedes 190E and it was very prone to this, after some investigation it turned out to be flat spots on the tyres (from locked up brakes)

The big clue in your post is that it is more noticeable on smooth road surfaces.

Modern cars which have ABS should be less prone to this but it has happened on my E class estate over the years - when I went to France the super smooth roads highlighted the issue big time!

Have you tried new tyres?

Pricey but a clean sheet start

That was my initial hopes but 2 sets of tyres later and still there

 

[willg]

I picked up the S-class from Mercedes Poole this afternoon. I went out with their workshop foreman for a test drive and we both confirmed the issue is still present. He was sympathetic and did have some ideas (prop shaft or steering rack) for next steps, but couldn't offer any guarantees that it would solve the problem, as he put it, they were 'stabs in the dark' and they have exhausted the diagnostics available to them.

I'm rapidly spending money on what seems like a trivial issue, but one that is annoying on long drives and defies remedy so far:

MBS Southampton (4 visits)

• balancing (all wheels)
• tracking (all wheels)
• thrust control arm bushes
• gearbox and engine mounts (at my request for good measure)

Elite wheels and tyres Reading

• balancing
• sanding the back of the wheels where they mate with the hub due to an alleged uneven refurb job

Me:​

• Tried an 18" set of S-Class wheels from eBay​
• Tried varying gears at constant speed to see if engine speed was a factor​

Mercedes-Benz Poole

• balancing
• swapped the wheels with another complete set
• replaced thrust control arm bushes with ones from 4matic as per TSB

None of the steps above have resolved it.

The steering wheel still shimmers/vibrates at speeds of 40/50mph + and it continues apparently no matter what the speed (I've gone up to 70mph odd)

I'm going to take it to the Vibration Free people on the 10th of July to see if they can figure it out. Short of that, I guess I'll have to either tolerate it or get rid of it.

 

[DrewGardner]

That was my initial hopes but 2 sets of tyres later and still there

Wow! That is a tough one

 

[notsofast]

My last ditch effort I have used successfully previously is to get the driven wheels off the ground with the car on axle stands very securely and run it up in gear. You will likely be able to locate the source of vibration. You will get abs or tc warning lights because of the stationary wheels but that will clear once the car is driven again. Obviously there are hazards with this approach but as long as the stands are very secure and substantial, don't go under or in front of the car and do everything gently you will likely be able to see wheel vibration or maybe drive / prop shafts. Swap wheels front to rear and repeat to check everything. There is precious little at the front other than worn bushes, joints or discs that could cause vibration and these things are easily checked.

 

[willg]

A few updates: I went back to basics and had another wheel alignment check (as the check is free at kwik-fit and they have hunter wheel alignment equipment at my local branch).

It reports the car has got a bit of toe out on the front, and toe steer on the rear. Front right camber is a tiny bit off but within margin. I'm not sure if the toe out is enough to cause the steering vibration at speed (and why it wasn't detected/corrected at the previous wheel alignment).

I didn't get them to adjust as I don't want throw money away (and I'm slightly suspicious that these checks always reveal the alignment needs doing)

I've noted the wobble is worse around 55-65mph and reduces at about 80mph. It feels like wheel balance - but it's definitely not (three different sets of wheels all behave the same), so I guess sticking with the theory of rotational mass somewhere at the front, it could be radial runout on a rotor (how likely is that?), a wheel hub defect or a component of front suspension (although they've all been checked a few times). If we include the rear, then it could be prop shaft, coupler, diff or driveshafts I guess.

I would want to do the camber too (and will need the camber bolt kit for that) if I get the wheel alignment done again, but is it a big enough toe out to cause a problem?

 

[willg]

Went to the vibration free people today, took it out for a test drive with Steve one of their technicians. He noted the problem and also mentioned the tracking appeared to be off as the car pulled to the left. So we took it to a local garage he recommended nearby and had the alignment checked, it showed a slight toe out again (but different values to the readings above) so I had it adjusted. Unfortunately it did nothing to resolve the vibration problem. Steve said it felt like something in the power steering system, like maybe it's trying to assist turning at dead centre.

I have noticed it does seem more noticeable at straight ahead- but that's also the only time I can really take my hands off the wheel to see the vibration happening.

 

[pembssurf]

Have you had all 4 bearings checked for play?

 

[willg]

I checked them a few weeks ago using the 9 and 3 then 6 and 12 hand positions, the rears were solid. The fronts had a tiny bit of play which I mentioned to MBS, who said they would tighten them up when doing thrust control arm bushes. I haven't checked since, but I will confirm for myself.

I've ordered a dial gauge, so I can check the hub and brake disc runout too.

I should have insisted vibration free people did an on car wheel balance check to verify the balance of each complete front assembly of wheel, brake disc and hub in situ.

Forum posters with similar say this is design flaw in the car and cannot be fixed.

 

[willg]

I have recorded a slow motion video of the steering wheel shimmer at a steady 70mph:

https://photos.app.goo.gl/Z6TaYjyQa7CKFRtE9

The video was shot at approximately 120fps, so is about 1/4 the actual shimmer speed.

I was trying to work out what it could be based on the frequency of the shimmer and the frequency of known rotational components:

The car’s linear velocity is 70mph in the video, the car has a wheel diameter of 27 or 27.6 inches (wheels 255/35R20 front and 275/35/R20 rear according to the manual ) that would result in the wheels rotating at 14.5 - 14.2Hz (give or take). Eyeballing a 10 second segment of the slow motion video I counted about 33 oscillations of the steering wheel, at 4x the speed that would be 132 oscillations over an actual 10 second period, or 13.2Hz. That’s within 1.5hz of the frequency of the wheel rotation? Is that correct? If so, would that indicate something that rotates at the same frequency as the wheels e.g. discs, hub, drive axles.

 

[willg]

I've ordered replacement front brake discs as the second largest rotational mass after the wheels themselves I'm going to replace them as a precaution, this also gives me an opportunity to examine the hubs and wheel bearings.

I had the car up on the ramp at Mercedes Poole again the other day and I was able to check all wheels for play, the front two feel like they have a bit of play still (so I don't think MBS did tighten up the bearings). The play is very slight so I doubt that's a factor, but I will check the condition of the wheel bearings and and tighten them up - never done this before but I have purchased a dial guage and magnetic holder for this purpose so I can at least be accurate in my measurements.

Is it safe to remove the wheel bearing hub from the spindle to examine it and then put it back? Assuming I do not remove any grease in the process?

 

[Richteo]

I'd also check the calipers are not sticking. This has been a cause of vibration/shimmy in both my w211 with the brembo 4 pot fixed calipers and a BMW 540i previously. The solution was refurbished calipers in both cases.

I'm not sure what is to be gained by completely removing the hub: it will be quite clear with the disc and caliper removed if the bearing is rough. Easy enough to tighten, especially with a DTI but you will need a piece of hardwood or similar to knock the grease caps fully home via the outer lip without damaging them.

 

[willg]

I have replaced the front discs/rotors with new genuine mercedes parts from the dealer.

I thought initially it had improved or eliminated the problem when I first test drove it in the dark, but the next morning the problem was still there, no better than before. So it doesn't appear to be the brake discs. There's a slim chance backing off the pads to remove the calipers would have been a factor for the first drive after, but if the calipers were sticking would there be other symptoms like very hot brakes, squealing and pulling to one side?

 

[notsofast]

Sticking caliper pistons will result in pad drag with consequent hot discs even when driving normally. Also more brake dust after a while on the sticking caliper side..... Easiest way to check for free brakes is to jack the front wheels off the ground and spin the wheel by hand - should be very little resistance.

 

[willg]

I don't think it's sticking calipers then I have none of the symptoms and the front wheels spin freely when lifted. I also checked the front wheel bearings and tightened up the front nearside.

We took the car on a couple hundred mile roundtrip at the weekend and I was able to sit in the back and front passenger seat whilst the other half was driving. A few observations and theories:

The front passenger seat shakes when unoccupied.
I could feel sbutle vibrations in the floor even sat in the back of the car.

I am now wondering, having had the front of the car checked several times, if the problem is more likely to be driveline related or suspension related, and simply manifesting as a steering wheel vibration. The other half said she thought the vibration was more of a vertical than a horizontal one, possibly suggesting a failed suspension component?

I am pretty convinced I can feel it from speeds just above 30mph, but it doesn't become as noticeable/visible in the steering wheel until 50mph odd.

I am thinking of buying a vibration data logger then driving the same route repeatedly with it attached to various points on the chassis and suspension, downloading the data running a fast fourier trasnform to seperate it into it's frequency components and seeing if I can start tracking it down that way, either by isolating the exact frequency and tieing it back to a known rotational mass (in a more scientific way than eyeballing the visible steering wheel shake) or by honing in on the source of the vibration by finding the location at which it's at its highest amplitude.

It seems lots of people suffer with vibration issues that just go unresolved because of the lack of specialists knowledge required to resolve and because it's not a black-and-white issue like the engine failing to start. Wouldn't it be great if there was a go-to place where they had a full rolling road facility, a plehtora of vibration sensors they coud attach to the car and a hookup to the car's various sensors to read and cross-reference different RPMs (wheels, engine, propshaft, gearbox etc) to the vibration frequency. So getting these problems identified and resolved would be as simple as getting a service. This stuff must exist, just not readily available or accessible to us mere mortals.

 

[notsofast]

I agree - I also hate vibration through the car. It makes an otherwise fantastic car feel well worn. Of the several cars that I have experienced this issue with, all but one was down to out of round wheel rim(s). Did you try jacking the car up, placing a pointer on the inside edge of the rim then spin the wheel by hand?. An out of round of even 1/4" can be hard to discern without a visual point of reference but I have experienced quite notable vibration from dinged rims barely 1/8" or even less. One pothole is all it takes especially with the such low profile tyres and wide rims.
Another idea I had previously but never tried was placing a go-pro or similar pointed at the edge of the rim and get it up to speed. Not sure if the vibration would be visible but certainly a low cost option to try if you have access to a camera.

 

[notsofast]

One other though is to inflate the tyres to the maximum permitted and find a very smooth tarmac car park or road. At slow speed (say 15 - 20mph max) if you can feel the steering wheel vibrate slowly then you can almost be certain it is one or both of the front wheel rims. I have experienced this but it needs to be an extremely smooth surface. Inflating the tyres hard will remove some of the compliance that masks the issue. My experience also is this will be most noticeable at a particular (slow) speed but I don't have any theory to explain why.

 

[willg]

Mercedes Poole apparently put a completely different set of wheels and tyres on the car and it still had the vibration, so at the moment, I'm working on the basis that it can't be the wheel themselves.

One interesting thing came up when the car was on the ramp at Mercedes Poole recently without the engine running, there was a metallic clicking noise coming from the area of the torque converter housing when the rear wheels were rotated by hand. They suspect the torque converter needs replacing.

I took the car to Star Motor Services in Reading, who I've used for 8 years or so (when I used to live in Reading) as the car is due a service and I wanted a second opinion, they said the torque converter has gone out of balance probably because weights have come off it (hence the metallic noise when rotating rear wheels) and that's the cause of the vibration. I've authorised them to go ahead and replace the TQ with a new genuine mercedes part.

Of interest to some: they did look at sending it off for refurbishment, but the company they use in Bristol cannot refurb later Mercedes torque converts because some parts aren't available to them/cannot be repaired.

I should get the car back by the weekend and be able to confirm if the problem is resolved, but I wanted to update this thread now in case I forget and it's useful to someone else.

 

[willg]

Oh and also of interest, the car had done 28,000 miles when I got the car (and the vibration was present then), admittedly it's 7 years old, so high mileage isn't a factor in this type of failure apparently. Full MB service history too.

 

[notsofast]

I would imagine out of balance TQ would be engine speed related rather than road speed, however, I hope you have the problem nailed.

 

[willg]

Yeah that's my concern too, it didn't seem related to engine speed at all, but there was definitely a metallic noise when it was on the ramp as I heard it, have a video of it and Star reproduced it, so something wasn't quite right in the TQ area, maybe it was causing resonance elsewhere too...clutching at straws now.

It could be both an expensive and dissapointing exercise in terms of fixing the vibration problem though. I'll update you once I have it back.