500E Driveshaft Vibration - PeachParts Mercedes-Benz Forum

Bryan Harter · #1 08-20-2001, 05:57 PM

Has anyone experienced a driveshaft vibration that occurs at 58-68mph. The steering wheel shakes as well as the shifter.

I found one post that mentioned it, but it turned out to be a bad rotor in combination with a damaged front suspension component.

It definitely feels like a shake in the steering, I had the rear transmission mount replaced, but that only damped it a bit.

There aren't any visible signs of damage, but why would the driveshaft be out of balance? Is this a warning sign of a bad flex disk ready to come apart?

The MB dealer looked at it and replaced the mount, but it is still there. They suspect the tires / rims. I just put on some 18x8 with 235-40-18 Dunlop 9000's. They are a bit harsh but I am not convinced the vibration is due to them. The rims are 25 mm offset which are a good fit on the front physically, but different from the 16x8 ET34 that was OEM. It is possible that they are the cause.

Any insight would be greatly appreciated.

-fad · #2 08-20-2001, 06:56 PM

after reading that tires/wheels were recently replaced, I suspect the tires/rims to be the primary cause (especially if the car acted correctly before the change).

if that is not the case, possibly a number of worn items are contributing to this fiasco: suspension, linkages, bushings, steering box, out of round tire, bent rim, internally defective tire, warped brake disk, externally defective tire, etc.

in my experience, the supernatural "possessed" steering vibrations are most often caused by the need for proper wheel balancing; easily corrected by a "fine" setting on the wheel balancer, and/or in extreme cases wheels balanced while mounted on the car

Usually, when new tires are purchased, the shop places the wheels with the least weights (correction) & truest wheels on the front for obvious reasons.

It is imaginable that you have a tire/rim that is bad (tire out of round, un-true wheel). Usually if a tire/rim is bad, one would be able to spy external culprits as spinning on the balance machine. It will not be a smooth perfectly round rotation visually but look like an uneven gyration. External tread and side casing abnormalities will be also observed and identified similarly.

Also, if a suspension piece is in need of r/r but not yet failed(bushings, steering box, linkage, shock, strut, etc.), the condition may be more pronounced/ accentuated.

Had a flex disk go bad in an Alfa before (same driveshaft set up as MB), fyi- sounded and felt like a loud forceful banging/ heavy thunking of dense rubber underneath my seat/ against the chassis/ trans tunnel (any speed but more readily observed and more violent on the freeway). It sounded like a washing machine on the final damp-dry spin cycle with all the clothes biased to one side- - but in this case the steering wheel was not affected.

...has the car been in an accident?, if so this "repaired" condition may make it susceptible in non-perfect conditions

sorry can't help you with the offset q's

good luck and keep us posted on correction

-fad

MBlovr · #3 08-20-2001, 08:04 PM

Bryan,

You owe it to yourself to eliminate the tires / wheels as the cause first. Swap wheels around on the car or better yet get a set off of another car and try those or better still have your tires / wheels tested on a the Hunter 9700 (Road Force) machine. The next place I would look would be the idler arm bushing.

Bryan Harter · #4 08-20-2001, 08:29 PM

The dealer claims the problem is "much" less noticable with a borrowed set of rims/tires. The OEM rims are not mounted right now but the dealer did a road force test and rebalanced the wheels and tires when this all began. The rims/tires were purchased new from TireRack because the OEM rims were in dire need of refinishing. The results of the roadforce were faxed to the TireRack and I warned them that one tire was suspect but I wanted the dealer to do more investigation. The problem has seemed to exist in varying degrees for some time, it was the reason I bought new tires as I thought the old Dunlop 8000's were past their useful life and out of balance.

The steering was redone, rebuilt pump, gearbox and many new parts including a new dampner. Didn't replace the ball joints.
Did do a 4 wheel alignment.

The rear trans mount helped the situation but it seems to be worse at times than others but always in the 55-70 range. I think it dampened the vibration but the source is still there.

The dealer tech mentioned the driveshaft as a possible source, but I am baffled.

I just had the front brake pads replaced and the runout checked on the disks, it was general concensus that they were good for one more set of pads before they would require replacement.

Still baffled....
Thanks for all the good feedback.

Mark Herzig · #5 08-20-2001, 09:19 PM

Bryan;

The same dealer mentioned an out of balance drive shaft to me also. I experienced higher than normal steering wheel vibrations after I had a blow-out and lost a good rim. The replacement rim had some minor curb damage. After checking around, I believe the problem will be fixed with a new set of wheels and tires. What complicated matters is that the vibration was comingled with the timing chain replacement, bad spark plug resistor,etc.. I think you remember all this earlier in the year... So I'd fine tune the balancing on your wheels and only consider the drive shaft balancing as a last resort.

As a side not, MB of Austin used a guy out of Atlanta to do the balancing. He also advertises in the Star magazine. I did talk to him and he said that the drive shafts DO go out of balance more than we realize...

Bryan Harter · #6 08-21-2001, 01:41 AM

My reason for buying the new Moda R6 / Dunlops was to eliminate the possibility of a problem with the old OEM rims, as they had a few scrapes and one was suspected of being dented.

The TireRack sold me the 18x8ET35 rims but they didn't clear the calipers so they sent some ET25 rims which fit nicely, but they may be the cause of the problem.

The MB dealers road force test indicated a bad Tire on the right rear that was not possible to bring into acceptable tolerance.
They rebalanced the set twice!

The guys at the TireRack have not returned my email when I told them about the problem. I really feel like it is more than just the tires, but until I can get something else on the car and drive it for myself I don't know. If it is the new rims/tires, I am sure we can resolve it.

The MB dealer had trouble finding a suitable donor to borrow a set of wheels last week when they had my car. They eventually found a set that fit but I didn't get to drive it, so I am not convinced at this point in time that it was the source of the problem. They were kind of wishy washy on the whole thing,
I am going to meet with the service manager tomorrow morning.

This whole situation has been going on since late March, I have been out of town alot, but each time I pick up the car it is something new but still the problem exists.

#7 08-21-2001, 11:16 AM

Bryan & Others,

I get a what I'll call a rhythmic "thrumming" noise at around 60-65MPH. Its not a vibration. People with me don't notice it unless I point it out. I saw a Tech Bulletin a while back that showed a fix which I believe involved rebalancing the driveshaft. Has anyone else had this problem? Anybody have this problem fixed or seen the TB?

Randy
'94 E500

Glen · #8 08-21-2001, 11:37 AM

Bryan,
I have a set of R6's on my 16V and really like them :-)
Sometime next year, I plan to upgrade my E500 with 18's also, so I'd love to see some pix of your car if possible.

Thanks.

Bryan Harter · #9 08-21-2001, 11:41 AM

Why is it that GM and Ford can design a driveshaft that doesn't need to be rebalanced during its lifetime?

I don't understand the design at all, but I find it peculiar.

German Over Engineering at it's finest....

Bryan Harter · #10 08-21-2001, 11:43 AM

I haven't taken any pix since the wheels were added but I do have a full series of pix on the Euro Headlight conversion....
I just need to find time to scan them all and post them somewhere. I don't have my website anymore...

-fad · #11 08-21-2001, 11:49 AM

was this condition occurring with the original set of wheels (before replacement from Tire Rack)?

...if so, you are probably correct in your assumption that the condition is not (solely) caused by the new tire/wheel/ offset/etc.

...I'm thinking that the sl500/500sl 8 hole 16" should not be too difficult for a MB dealer to locate and swap for testing on your car...

I have an extra set of 8-hole chromies from a 92 500e that I'd offer you, but I'm in the SF Bay Area and you are apparently out of state.

...maybe its time to have a mb suspension specialist look at your vehicle, and/or another dealership's most senior tech/ shop foreman/ factory tech roundtable discussion?

-fad

Bryan Harter · #12 08-21-2001, 11:59 AM

Glen,

I really like your 16V with the R6.
My 500E is also Smoke Silver, I think the bright silver wheels look great with the Smoke Silver paint.

I wanted to buy the 3 piece OZ Mito, but thought these would be much easier to keep clean.

This is a pic of my car from a few years ago with Lorinser RS90 wheels. I really liked them but they were a bit flashy.

Michael · #13 08-21-2001, 01:23 PM

The driveshaft center support bearing has been updated several times since your car was built. A few months ago I replaced my motor mounts, the transmission mount, and both flex disks all at the same time. Well, a similar vibration developed but only at 25-28 MPH. Upon replacement of the center support, the problem went away.

If I were in your shoes I would have that right rear tire re-balanced while I watched. When they spin the tire up, watch for run-out or a hop. Watch & make sure it'll balance too. Then I'd do the center support, but I doubt it's causing your problem.

Bryan Harter · #14 08-21-2001, 01:43 PM

Thanks for the suggestion Micheal.
The dealer's road force test indicated that the amount of weight required to balance the tire/rim on the RRear was not within (MB?) tolerance.
I was amazed at how much weight had to put on the rims in general, almost 4 oz on one. They positioned the rim/tire to offset the weight differences when they began the balance.
The road force test did not identify an out of round problem, I think it would have if one existed.

I will talk with the dealer about the flex disc and bearing.

Michael · #15 08-21-2001, 01:58 PM

Bryan,

Get the Rack to send you at least 1 new rim! 4 ounces?!?

That's way too much-clearly those rims are too tough to balance. Did you try dismounting then re-mounting a different tire (say, swapping 2 tires/rims) to see if it still wouldn't balance? If you do this and the problem remains, then you KNOW its the rim. Get Tire Rack to help you out. Luke??

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