Update - Steering Vibration better, need more input
 

Could a worn out steering coupling or steering gear be a cause of an intermittant steering wheel vibration? What about the rubber mounts and bolts that mount the steering gear - shop manual says replace bolts, don't reuse?

The steering linkage is tight. But, when I push/pull the wheel at 3 and 9, I do get a clunk. The rest of the steering linkage is tight and all less than 13 months old - including tie rods, drag link, idler, steering shock. Wheel bearings are good. It COULD be the tires, I will rotate them. Based on those results, I'll get a GSP 9700 involved as necessary.

But would like to know if steering gear or coupling could cause an intermittant vibration, that's particuarly bad on fresh asphalt and smoothest on good concrete...

-brian

P.S. I want to thank (again) the forum members that have helped me so far. Changing my struts made this vibration slightly worse than it was, BUT it reduced 99% of the vibration I WAS feeling near the gas pedal - particularly around town I have no vibration anymore in the gas pedal.

You MUST go to the source of the vibration. Non rotating parts such as a loose linkage, slack in steering etc. are not vibration sources, they are vibration transmitters/aggravators. If you have a rotating assembly that is vibrating for whatever reason, shocks, linkage, steering boxes, columns, etc. will worsen the vibration because this looseness allows the rotating part to have impact against these loose parts as it bangs back and forth.

You are moving in the right direction. I will bet a dollar to a hole in a donut that the SOURCE of the vibration is tire balance. For this you usually don't need the sophistication of the 9700. Any good computer balancer in proper working order is capable of adequately balancing your wheels. The key is that you MUST use balance weights on two planes, inboard and outboard. It is very common for the tire stores to NOT use a weight on the outer plane because some customers complain about scratching their aluminum or alloy wheels.

Where the 9700 comes into play is when there is a tire with excessive road force variation (stiff spot.) The 9700 has a pressure roller that loads the tire while it rolls and measures the road force. It can resolve where to rotate a marginal tire on the rim in order to minimize the effect of the stiff spot. Very few tires, depending upon brand, require this level of attention, a competent operator on a decent computer balancer will get the job done.

The decent computer balancer is the easy component to find, they are all over your town, now the competent operator is a different story.

Best of luck,

I agree 100% with Larry Bible.

Get a proper tire balance with wheel weights on both the inside and outside lip of the wheel.

You'd have to have a tire with excessive "wheel force variation" that would cause a normal tire balance machine to be unable to balance your tires.

In other words, all tires have soft and stiff spots around the side wall of the tire. If the difference between the soft spots and stiff spots is too great, wobble will develop, and a normal machine can't correct for this. A GPS 9700 can identify these spots on the tire, and show the operator how to rotate the tire on the wheel and where to put the weights. If a tire has too much wheel force variation, then it can't be balanced.

But he's right in the 90% or more of these type of vibration problems are caused by improper tire balancing.

I don't want to downplay balance, but I have reason to believe my mechanics shop did a good job re-balancing the tires first balanced by Costco.

In the event that I have a flat tire in an unknown place, I may not be able to find a fantastic balancing shop. So, I'd like to eliminate both (a) the immediate source of the vibration and (b) looseness which can aggreviate the vibration (as mentione by Larry).

This is why I'm particularly interested in experiences with the steering gear.

Thanks, other suggestions are welcome as well.

md21722
 

ONLY get your tires balanced by an MB TEch with the machine mentioned by Larry and Suginami OR at a MB Dealer. This may sound trivial however this is absolutely CRITICAL. Good luck!

Tee Hee Hee - I recall the story of my 1995 E300 (sold). The MB dealer here in town was unable to get the vibration it even after replacing a tie rod and balancing the tires three times. They claimed there was no problem. I even had the tires balanced on the car and there was still a vibration. Balance isn't everything.

-brian

I've got a similar issue with my '87 wagon. Haven't been chasing it too hard because I've been busy with the non-Mercedes parts of my life!

I've got a steering wheel vibration which comes & goes. Mostly it's not there, but every once in a while it appears. Highway speeds only - greater than 60MPH. Unlike everybody else, I already have had a GSP9700 balance done on this car. It passed with flying colors. The car definately was smoother following the balance - but the intermittent vibration remains.

Personally, my bet is on lower control arm bushings.

md21722, is your car a 1995 E 300? If not take the advice and possible save yourself some money. I had my lower ctrl arm bushings redone and drive shaft loop. Only after that AND tire balancing were my vibrations history..

I've had new and old tires balanced several times in some cases with no change in results.

Then one day, I buy a different set and voila! No more vibration!

Sometimes it's the tires themselves...;)

This is true. Only michelins hold up on my sdl. Weird, I know.

The car is a 1987 with dealer control arms replaced in August to cure a HARSH intermittant vibration that was more like a thumping. I keep hearing about driveshafts - what all was done to yours? MY center support bearing and support are original but at last check were "okay" - not torn and bearing not making noise to mechanics stethescope. Maybe I should change them anyway?

Can I conclude that the steering gear or steering coupling would not aggrevate vibrations in the system?

Hi jcyuhn -

If you do track down your vibration, please post the results. My E420 has some odd vibrations in the front end at highway speeds too. On the surface one would think it was tire balance - but the E has been there through the original wheels, multiple balances, new wheels, new tires and new tires again. We can rule out balancing!!!

Over the past year the front wheel bearings have been replaced along with the center link and dampener. So, that leaves things like bushings as you noted.

Aside from the odd vibrations at various highway speeds, the car is very sensitive to changes in the pavement surface - changes direction easily, bumps & expansion joints take the car a couple degrees off course. Nothing too annoying, I subconsciouly correct and don't even think about it anymore. But then I drive some of my friends' newer cars (LS400, C240 and 540i) and get secretively jealous over how smooth their steering feels!!!

I used to live in Plano and the roads were much smoother. I moved to Seattle last year and roads are terrible, so this has been bugging me alittle more than it did. And I will confess, I changed the rims from the OEM 15" to 16". The current tires or Pirelli P3000s - so far I'm very happy with them (on par with Michelins for ride quality and road nise).

John,

How many miles on your car? In some cases shocks and subframe bushings are to blame. I went out West to Montana and the wind gusts blew my car ALL around. Go from pavement to bridge and the car would jump - hard to keep in lane! Two local MB mechanics suggested "weak shocks". I replaced them and the subframe bushings which were shot and now the car is much tighter. I haven't been in really windy conditions, but overall the car follows the road better and the front and rear of the car follow one another. So far, it seems the feathering on my front tires has gone away too...

Well, I can tell you what I DO know. If you put your hand behind your seat while driving, place it on the center hump. If you feel the vibration there, it very well could be the loop bearing and or rubber bushing. One guy had his lower ctrl arm BUSHINGS replaced and still had a vibration. After thousands of dollars, he found out the bushings were put in diagnally or something and were the source of the vibration all along! Yuck! I know how frustrating this is and wish you the best of luck.

Hi Tank -

Can you educate me alittle, what is "loop bearing and or rubber bushing"???

Thanks,

John

TANK,

I appreciate everyone's comments.

767Flyer and myself BOTH had incorrectly installed front lower control arm bushings. The bushings are part of our problem, but not the ultimate fix. Both of us are still working on it.

I have not tried the center hump test, I just put my hand on the side of the center console. I do get SOME vibration there, but its not bad compared to when I've got rear tires out of round... Do you feel ANY vibration there? I have the parts on my shelf, but have not yet installed them as I did not think driveshaft would cause steering wheel vibration....

John,

Underneath the exhaust heat shield is the center support for the driveshaft. Its a rubber donut that bolts to the body. A bearing that is mounted to the driveshaft fits inside this donut. When its really bad, the donut has broken away from the mount or the bearing howls.

Sure John, to the best of my recollection, the driveshaft, really 2 driveshafts joined - if you will, has something called a center support loop. Within this loop is a rubber "grommet" that holds a bearing by which the driveshaft turns. On my car, the rubber had a slight dip in it form age or sitting- I am not sure which. This defect gets worse with time exponentially and causes vibrations everywhere eventually. It's not difficult to put on, just time consuming because you have to remove stuff to get to it. I am also going from the experience of a 126. I have not owned another mb and assuming others are set up similarly if not the same. There may also be a pic of one on fastlane parts if you do a search..

md21722 - Yes, I did have vibration in my center console and pass seatback also.

Thank you for the explanation. The car is going into the shop to track down a vibration when the car is put in drive/reverse. In that post, everybody is come back to the ignition as the problem. Overall, the ignition appears to be functioning well.

I'm leaning towards a more mechanical issue such as the exhuast system and transmission have some counter tension. The tranny was replaced about a year ago along with engine and transmission mounts. The tech is guessing that when the car was re-assembled, the transmission and exhaust were tightened with no stress on the chasis. So, when the car is on the road, new stresses, hence the vibration.

Anyway, we're going through all this on Monday, so I'll the center loop as something to check. A couple hours of the car in the air and a Tech at my disposal - priceless! Actually, I'm quite sure they will find a price!!! Thanks for the help.

I've had the steering vibration across two sets of tires, so it isn't that. It's also been consisent across front-to-rear tire rotation.

I've got new tierods and drag link, and just put a new steering shock on while I was under the car for the 120K service in August. (Man I hate changing the transmission fluid, has to be my least favorite task.)

I think what it boils down to is that everything rubber deteriorates on an older car. The only way to make it feel like new is to replace all the rubber. So subframe bushings, lower control arm bushings, the various links in the rear suspension, etc.

I know what you mean about newer cars feeling so much better. My other car is a '98 E-class, and it feels so much smoother & tighter than the 124. It's not so much that the 124 is bad, it's actually pretty reasonable, but the new car is just so superb. It's so smooth - I can't tell the difference between 50MPH & 100MPH, side winds don't phase it. I almost understand why people buy new cars...

Hi jcyuhn-

Here I am fighting the new car bug and you say how much better your '98 feels!!!

I agree with you on the rubber parts. In another post I'm trying to get a vibration taken car of at idle in drive/reverse. If we can that taken care of, then I'll start in on the suspension (struts, shocks, bushings, etc.). If vibration at idle can not be located, then I'll start looking at new (or newer) cars.

Before buying the '95 E420, I test drove a '98 E430. That car seemed "shift happy" with the 5 speed transmission. In city traffic there were many 2-3 shifts. I opted for the '95 because the ratios were abit wider, less shifting and it seemed like a smoother ride.

Since you have both, how would you compare the daily operation of the two vehicles?

md21722,

Since you have already had the wheels rebalanced at a different shop, it is time to find a 9700. I disagree about this being done ONLY by an MB dealer. There are plenty of 9700's around. To find one go to: GSP9700.com There is a locator on this site that will tell you where there is one in your area.

Remember, when you are replacing/repairing such things as suspension components and steering couplers, you are not going to the source of the vibration, you are only correcting things that are making the vibration slightly worse. Don't get me wrong, all these things should be in good shape. But, you could easily spend a fortune getting all these other things in perfect shape, but will still have a vibration if there is a source of vibration.

By far, the most common source of vibration is the wheels and tires.

You did not say what kind of tires you have.

Good luck,

Thanks for everyone's comments.

The rims are new-style factory 124, with Michelin MXV4+ tires.

My mechanic was too busy to rotate or re-balance my tires. I re-checked the front end again and noticed loose wheel bearings. I tightened them, and there was a SMALL improvement.

More troubling, is I believe my transmission and/or driveshaft is a big part of the problem. The vibration becomes an issue after 60 MPH. Shifiting manually into 3rd gear makes a distinct improvement in the vibration - at 60-77 MPH. At 77 MPH, the car does feel a little wierd in third, but at 72, it's much more "solid" feeling. I think at 77, a resonance might occur from tranny to rest of car.

The tranny has known issues, including reproducable:

(1) rolls backward downhill on grade (easily)
(2) rotating driveshaft makes "klunk" noise. driveshaft havles themselves fit good - verified by my mechanic who "promises me" its the tranny

and intermittant occasional problem listed above, and a fast, harsh vibration (happened less than 5 times) when floorboarding car onto freewayat it reaches high RPM - makes me pull back off gas pedal - then goes away

I've replaced other suspension components in the past to cure various other problems including harsh intermitant vibration (front lower control arms), wind sensitivty/ride height (shocks, spring, subframe mounts), extra play in steering (worn components). Now its "tuned" into this. Most people don't seem to think driveline can cause steering wheel vibration, and I'm won't change the tranny specifically to reduce vibration (the vibration is annoying, but tolerable). I'm going to replace it because its starting to act up more frequently and I don't want to be stranded somewhere should it finally go, particularly with winter coming, and trips to family/friends for coming holidays.

Can't go wrong here! I still think it's a combo of your lower ctrl arm ball joints incorrectly installed and perhaps the ds loop and bearing and/or dive shaft is out of balance...

I'll try one more time.

If it is not a part that rotates more than 360 degrees constantly as the car goes down the road, it CANNOT be a source of vibration. It CAN, however, be something that will allow the vibration to be more noticable.

The rotating parts to which I am referring would be tires, wheels, rotors, bearings, driveshaft and associated components, halfshafts, transmission rotating parts, engine rotating parts, rear axle rotating parts.

So you have two categories of parts, rotating and non rotating.

By far, the most likely vibration culprit is the wheel/tire combination, the second most likely is the driveshaft components.

The worst offender for non rotating parts are the motor mounts. Anything else in the suspension and steering system can aggravate mostly wheel imbalance.

Another thing you should pay attention to when analyzing a vibration is its speed. The driveshaft spins at an RPM about three times greater than the wheels. You should keep this in mind when trying to isolate the source.

Outside of bad motor mounts, you are chasing your tail replacing all sort of non rotating components in an effort to eliminate a vibration. Although these components should, of course, be in good condition, you cannot eliminate a vibration by replacing them. If you are on a campaign to replace every non rotating part that might be causing exagerated vibration, you are on an almost endless path until you correct the ROTATING SOURCE of the vibration.

Good luck,

Larry,

I'm not sure why you have to "try one more time". I agree with you.

I did NOT change suspension parts to cure vibration. The ONLY exception was the front lower control arms, and that may not even be considered a vibration. It was a thumping/vibration that occurred at lower frequency than vehicle speed, and replacing those parts cured THAT problem, and I haven't experienced anything like it since.

Tranny behavior is getting worse and will be replaced. Whether or not it makes my vibration go away is secondary to having a solid, good working tranny.

One question Larry - can you say one way or another if tire balance can cause an intermittant vibration? (assuming wheel weights are NOT flying around on the rim). I've always believed tire balance is either good or bad, it ain't intermittant.

Thanks.

TANK,

Why do you call the driveshaft support and support bearing a "ds loop". I've never that before.

Hi Brian,

Wheel balance / vibration issues occur at different speeds and at different temperatures. As the tire heats or cools down, the PSI changes and this can influence the tire balance or make flat spots more noticeable.

If you replace transmission, have them replace transmission mount, flex-disc, center loop (where the two dive shafts are joined together) and differential mounts. Short of the axels, this take care of every rotating part past the engine. Except for the differential mounts, all of this stuff is coming off anyway, so replacing them doesn't add any labor cost, just parts.

Also, have a friend idle the car at the various RPMs where you know the vibration kicks in. While he/she is idling the car, put your hand(s) on the engine (like the plastic covers over air filters & wear gloves!) and see if you can feel a vibration with the same frequency/characteristics that you're feeling while driving. If you do, but you don't feel the vibration in the cabin or steering wheel, then know at least the motor mounts are doing their job. Likewise, it is something past the engine which is magnifying the vibration while you're driving.

If both front tires have minor imbalance, it can cause a small intermittent vibration in the steering wheel. I've had this happen on one of my non-Mercedes cars. The relative position of the two front tires makes the vibration come and go. If one tire is "pushing" just as the other is "pulling" the two working together can generate enough force to be noticable in the steering wheel rim. Drive around a bend in the road and it disappears. The outside tire has travelled farther than the inside, and they are no longer aligned just so. My old Taurus SHO used to do this when both front tires were ~1 ounce or so off. Not enough for either tire to cause a bad vibration on its own, but enough for them to jiggle the steering wheel by working together.

- Jim

Why do you call the driveshaft support and support bearing a "ds loop". I've never that before.

Sure md21722, it's actually a term from the far reaches of the "Tank" brain and NOT and industry wide term. :D :D I used to be in sales and now I am in computers. Since I've been in this industry Ifor a couple + years now, I have a tendancy to make acronyms out of everything.

Try working for Ericsson - a bunch of Swedish engineers - we can't say sentence without at least 5 acronyms! Mix that with Swedish and every document looks like alphabet soup.

been there/done that/got the Vibration T-shirt (see my previous postings).

To all with front end vibration - LISTEN TO LARRY. I had a terrible time with front end vibration between 72-77 mph....had new tires, shocks, balancing, blah blah blah. Then I took it to a MB dealer and had them balance it on a 9700 - what a difference - new car feel with 252K miles! Smooth as silk at interstate speeds, all day long. Repeat after me - MB front tires MUST be properly balanced. MB front tires MUST be properly balanced....

JoeB

Yesterday I replaced the center support bearing, rubber mount, rear driveshaft bushing, and front and rear flex discs. Drove 275 miles - no difference :)

The bearing was little loose and I heard the balls spin around inside. The mount was cracked, but not enough for light to shin thru. that mount is VERY tough. I have seen (yesterday on a 76 450SL) mounts where the middle was completely separate from the mount, though. Three washers were missing off my old flex discs.

This may not apply in all cases, but in mine, I think unless the rubber fails miserably, it may not need to be replaced....

On the test ride, shifting into 3rd gear makes the ride a bit smoother. But not at 77 MPH. At 77, in '3' or 'D' there is something not right. I am pretty sure its been there thru several sets of tires, a new set of front wheel bearings, etc etc.

I'll have my tires checked on a GSP 9700 anyway, just to be sure. could be that something is causing all my tires to be chewed up a certain way :confused: .

Thanks.