Author Topic: Troubleshooting high speed vibration  (Read 1021 times)

rumb

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Re: Troubleshooting high speed vibration
« Reply #15 on: 19 August 2020, 05:30 PM »
A few years back I had a conversation with URO parts regarding flex disks. Huge debacle over on benzworld where the moderators would not allow URO to be a forum sponsor. Even though 85%+ forum members want them to be a sponsor the mods had it in for them.  I took the position of going out and actually learning from URO and corrected many false assumptions they were making to the point that someone then attacked me as a shill for URO.

URO made flex disks for several models of MB (R107 and I think W126) and they were a true disaster. They could make the same shape, but without the magic MB rubber formula they would never work.  Any other supplier faces the same challenge - MB just wont give them the rubber formula. URO did extensive testing and decided they could never make one as good as MB.

Speaking of URO, as MB gets out of the parts business URO has been backfilling and makes a lot of MB parts.  URO is also a OEM supplier to MB.
'68 250S, '77 6.9 euro, '91 300SE, '98 SL500 '14 CLS550

ptashek

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Re: Troubleshooting high speed vibration
« Reply #16 on: 20 August 2020, 03:51 AM »
Now come on, your presence here is very welcome, and not an annoyance (not to me at least) even if we disagree on things due to different experiences. Just a part of life. Let's file this one under "continue to agree to disagree" and move on.

I wish those companies would openly say, if that is the case, listen we're not really able to make what MB make, because we're to cheap or lack the engineering capability, or simply can't for legal reasons. That ain't going to happen though.
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ptashek

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Re: Troubleshooting high speed vibration
« Reply #17 on: 20 August 2020, 03:56 AM »
URO did extensive testing and decided they could never make one as good as MB.

"As good" as in service-life, or performance? Service life is less of an issue, if the final cost due to more frequent replacements does not run higher than OEM parts would cost.

Performance can be tricky. The part may not perform as good as OEM, but is still performing within safety limits. Or it's total crap-a-palooza (seems to be a theme with URO?).
1993 "Pearl Blue" W124 280TE
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rumb

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Re: Troubleshooting high speed vibration
« Reply #18 on: 20 August 2020, 04:21 AM »
Unfortunately those specific flex disks tended to explode.  :o :o

I have used a handful of their other parts that seem quite good. Turn Signal stalk for w126 appeared identical and has been fine for years now.
'68 250S, '77 6.9 euro, '91 300SE, '98 SL500 '14 CLS550

john erbe

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Re: Troubleshooting high speed vibration
« Reply #19 on: 21 August 2020, 05:53 PM »
In my case it was a wheel bearing. Vibration started in around 85. Find a tire shop that has the now hard to find machine that can spin the wheel on the car. Helps locate the problem if it's one side vs the other.

floyd111

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Re: Troubleshooting high speed vibration
« Reply #20 on: 02 September 2020, 07:54 PM »
"We can't make them the same way Mercedes does for copyright reasons.  Since physical shape is important for fitment, we have to sacrifice material quality.  We use less expensive metal barrels that the bolts go through, less expensive thread that goes in the rubber, and we have to use a lesser quality rubber material.  Since Mercedes lets us and a few other use their original molds, we are required by Mercedes to grind/scratch off the Mercedes part number and Mercedes star if present after we make our own versions.  People often mistake our products for genuine Mercedes because of the part number being scratched off, but the reality is that what we make is not anywhere close to a genuine Mercedes part.  We're not even allowed to sell genuine Mercedes discs even with the numbers and Star scratched off. If we did we'd be paying large fines and/or be in jail.  That's not to say that we don't make a good product, but our viewpoint is that we want to offer a product that is affordable to the masses, and if it vibrates a little at high speeds then that has to be better than a damaged/broken disc." 

I've worked in the industry for a few years. Not a single company, especially what can be considered a Tier-1 supplier, would ever issue a statement like this to a random person, let alone disclose such detail. This is an extremely hermetic world, especially when it comes to anything IP related. Unless you can furnish verifiable proof that these companies said this, I'm calling bullshit on this one. I'll happily eat my hat and apologise if you do, and we'll have this debate settled once and for all.

Lucas, given your age and exposure, you should know that experience doesn't always make us the wiser.   I have no idea why they were so open with me....maybe because I questioned them about why the Mercedes and aftermarket ones were made from different materials but had their company name on them?  Even the Shore hardness was off between the two.  One would bend easily, and the other one was hard as a brick.  With your credentials, I'm very shocked that you don't know that what they make aftermarket is never the same as what they make for Mercedes Proper.  It's common knowledge that on something like this that the same mold is used, but different materials are used. 

These emails took place one year to one and a half years ago, and I cannot place them at the moment,and I may not even be able to, as I delete emails regularly after they're a month old.  So there is no way I can show you proof of the correspondence.  It really bothers me that you feel I'd make something like this up.  I ask is that you give me and everyone else the benefit of the doubt before you call bulls*&t.  However, if you leave this conversation thinking as such, then there is nothing I can do.   I realize that my presence on here annoys you to no end....and I'm not even sure why....but do know that I care.  I wouldn't purposely lead anyone astray on a subject matter such as this.  It's just not who I am or what I'm about.

May I chip in here, and give my 2 cents?
As a former (extremely unsuccessful) Meyle and Febi distributor for Taiwan, I also have bits of data to share.
I hear talk of Uro, Febi, Meyle "research and development"
I can't judge their complete history from day 1, but in these modern times of greed and disposability, one has to seriously take all that "research and development" with a barrel of salt.
And, while I don't doubt for a second the mails that UTC received, I would advise the very same, regarding the content of those mails.

What these German (but quietly Singapore-based, mostly Asian-run-offices) aftermarket companies do (in most cases) is ask their Singapore office to scout Alibaba for Asian producers of whatever part type they are looking for, hand them specs, and then await quotes, samples and lead times.
There then may be a a check, but only THEY know to what extent that happens, depending on the part at hand.
After that they decide on the cheapest supplier and stuff the re-branded boxes for global distribution.
As long as the chinese supplier doesn't rock the boat, there is continuance.
As long as there aren't a lot of end-user complaints, resulting in a drop of sales, there is continuance.
In all other cases the complete process recommences. No glory, no mystery, no rocket science.

As far as copyright is concerned, one can only be informed if one were to know each genuine part's independent status. Even at MB Stuttgart there isn't a person alive that could tell you, without first assembling a back-up army of lawyers and consultants for a deep quest into the warehouses full of legal data.
Copyright only applies if the design has a unique technical or aesthetic feature that was patented by MB. And, to complicate things even more, it would have to be an issue important enough for MB's legal department to actually care about, and only after making an assessment if the case could actually be won in court, -and within what time span and at what cost.
Only after all of that could there  possibly be talk about 'patented rubber make-up being a hindrance to producing identical quality pattern parts. -Unlikely" would be my personal assessment.

Next up is what most of us know. Mercedes used to do all their massive research and development themselves or in close tandem with the likes of Bosch, SKF, etc.etc.
They either produced in their own factories, or it was done in close tandem by big, solid European producers.
These days we are finding the "Made in China labels" more and more, so one may have varied opinions about what exactly is to be expected from a genuine Part as to who exactly is doing the research, development and QC and how much of it.
What you can be sure of is that whatever anyone of importance at MB tells you is -at best- going to be a microscopic insight in the production of a microscopic part of the parts that mercedes produces and the (very temporary) policies regarding that microscopic segment.

Was that a rant? In that case, //rant off// ;D
« Last Edit: 02 September 2020, 08:02 PM by floyd111 »

TJ 450

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Re: Troubleshooting high speed vibration
« Reply #21 on: 03 September 2020, 02:58 AM »
Can you still buy the Lemfeorder boxed flex disc? IIRC they had the MB star ground off, I have them on my 6.9. These were purchase back in 2014 though.

Tim
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Sonch

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Re: Troubleshooting high speed vibration
« Reply #22 on: 24 September 2020, 05:42 PM »
Bubbling this thread back up to the top with the suggestion about tires.

Was waiting to weigh in until after I got results --

I had the same high speed vibration on 1979 450 SEL at higher speeds. Just make sure you have the EXACT tire size/type recommended on inside of door jam. I had a perfectly fine set of NEW tires, had them balanced to no avail. Went back another time and more experienced tire guy said it was about the side tire wall being firm enough or something. . . need to be "HR" rated tires for higher speeds.

I know this sounds too obvious to be the answer, but HR tires at this size are NOT easy to find and are not produced as much anymore. I live in the "Motor City" (Detroit) yet had to order these suckers from California.

Anyway, as soon as I put them on and balanced, vibration GONE. So you might try this route before going too deep into discs etc

Design Drive Motors

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Re: Troubleshooting high speed vibration
« Reply #23 on: 26 September 2020, 07:52 PM »
Aside from making sure the flex discs are centered, and good, the reason engine or trans mounts can make a difference is that as the engine drops over time, it changes the angle of the driveshaft to the diff.  This may be a small drop. but because of the use of flex discs, and not CV joints or u-joints, I have seen it cause vibration problems.  I have also seen a rear mount on a transmission lift under load and the flex disc hit the bottom of the car (this was on a BMW with a guibo flex disc set up like the Mercedes). 

If possible, run the car up on a hoist, (after you lock out the suspension) and see if you can see any of the vibration at that speed.  Load the car up for brief periods of time by using the brakes and the gas.  You don't want to over heat the brakes, so make sure that you only momentarily do this, and give time between braking to let them cool.   Look for any vibrating parts, feel solid parts around everything (just don't burn yourself, or get caught in any moving parts!), look for mounts moving or flexing beyond what would be considered good, look for rear axles shaking, check the differential for play or noise on the pinion or the axle shaft flanges.  You may see something that is out of place.  I have seen wheel assemblies out so much that they bounce the rear suspension up and down, and I have seen driveshafts out so bad they shake a transmission.  I have seen engine mounts lift in two pieces.

It can be hard if the rear suspension is not supported as far out as possible because then you change the angle of the axles to the differential.  But if you can reduce the amount of flex here, you can get as accurate as possible. I often use a drive on hoist that has separate center lift jacks to support the rear control arms as far out as possible without rubbing on the wheel.

There area  few problems with this method to be aware of, but it can narrow down your issue, the problems I can think of are:
-Doing this on Jack stands, and going under the car is extremely dangerous, so please bring it to a shop and ask if you can watch while they do this.
-If your rear brakes are warped, this will not help, as when you apply the brakes, you will get a vibration from the warped rotors that may hide the true problem.
-If your front wheels are the problem, you wont find it this way
-If your tires are the problem, you may find it this way to see one spinning out of round, but if it is a tire contact load problem, you will not.
-The rear axle angles change from true driving, so it may become less accurate.

I hope some of this may help.  Its always hard to try and figure stuff out when your not in front of it, and even when you are, it can still be hard!
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Rolo

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Re: Troubleshooting high speed vibration
« Reply #24 on: 29 September 2020, 11:37 AM »
Bubbling this thread back up to the top with the suggestion about tires.

Was waiting to weigh in until after I got results --

I had the same high speed vibration on 1979 450 SEL at higher speeds. Just make sure you have the EXACT tire size/type recommended on inside of door jam. I had a perfectly fine set of NEW tires, had them balanced to no avail. Went back another time and more experienced tire guy said it was about the side tire wall being firm enough or something. . . need to be "HR" rated tires for higher speeds.

I know this sounds too obvious to be the answer, but HR tires at this size are NOT easy to find and are not produced as much anymore. I live in the "Motor City" (Detroit) yet had to order these suckers from California.

Anyway, as soon as I put them on and balanced, vibration GONE. So you might try this route before going too deep into discs etc

Not tires.  We addressed that 3 sets and 5 balancing ago.

TJ 450

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Re: Troubleshooting high speed vibration
« Reply #25 on: 29 September 2020, 10:15 PM »
FWIW, I’ve never driven a W116 or even a W126 that was without this sort of vibration. I eventually gave up trying to achieve perfection, so I’m keen to see what eventuates with this.

Tim
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raueda1

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Re: Troubleshooting high speed vibration
« Reply #26 on: 01 October 2020, 08:10 AM »
FWIW, I’ve never driven a W116 or even a W126 that was without this sort of vibration. I eventually gave up trying to achieve perfection, so I’m keen to see what eventuates with this.

Tim
Interesting and odd.  Your sample size is certainly bigger than mine.  I've only driven one other W116 (another 6.9) at speed other than my own, but neither vibrated at speed.   So smooth W116's are possible.  Mine has 15" bundt look-alikes and Pirelli 230/60-15's.  Flex disks are recent and the center bearing is new, though it didn't vibrate with the old one.  Clearly there's some pervasive yet mysterious phenomenon going on.  But I guess that's the point of the thread. :o 

I wonder if the vibrating cars had the driveshafts carelessly reassembled at some point - for exhaust work maybe, replacing flex disks, whatever.  It's very easy for them to come apart when removing and if it isn't marked in advance......   :-\   And I'd also guess that there are degrees of being out of balance.  If the shaft was put together just 1 spline off it would presumably be less out of balance than if it were 180deg off.
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Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

ptashek

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Re: Troubleshooting high speed vibration
« Reply #27 on: 01 October 2020, 10:21 AM »
Just a random thought - wouldn't a worn out rear transmission mount potentially cause this?
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revilla

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Re: Troubleshooting high speed vibration
« Reply #28 on: 01 October 2020, 10:33 PM »
Just a random thought - wouldn't a worn out rear transmission mount potentially cause this?

I suggested to Rolo something in those lines. I think it’s the transmission mounting bracket that was tightened (2 screws) when the car was still on jacks. Or they were tightened without letting the car sit first on its own weight and moving it back/forward a few meters until the trans and shaft found its free state positioning. I agree, a worn mount would cause it too except in this case the vibration started right after the flex discs replacement if I recall correctly.

We might be using a too-broad definition for the word “vibration”.
Tim, I understood he has a strong hammering type vibration felt in the seat through the chassis.  There’s the other soft type W116 vibration that I think you’re referring to felt through the steering rather.
The first type is unbearable and it would remove the fun part of driving these wonderful machines.
The second kind I can live with no problem there.
Robert
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TJ 450

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Re: Troubleshooting high speed vibration
« Reply #29 on: 02 October 2020, 09:53 AM »
Revilla,

Yes that sort of hammering vibration was what I had in mind, where the backs of the front seats oscillate back and forth.

Here’s a summary of my experiences:

450SEL: harsh vibration from 70km/h up peaking at around 110km/h which might have been attributed to the tailshaft but was never confirmed.

280S W116: steering shimmy and mild vibration through the seats at 110km/h. No work done to troubleshoot other than checking the flex discs and mounts which were OK.

280SE W126. Mild vibration through wheel and seats at 110km/h. All mounts and flex discs replaced and new Michelin Tyres, wheels balanced and aligned. No difference.

6.9 5866: Tailshaft noise/ whipping on acceleration, vibration through whole car from about 90km/h peaking at 110km/h. Appeared to be oscillating vertically.Centre support and trans mount changed, no go. No further investigation.

6.9 1432: vibration through wheel and seats at 110km/h. Seems to be in vertical plane. Everything in driveline and suspension replaced except struts.

560SEL W126, smooth except wheel shimmy at 100km/ish.

W201 190E. 100% smooth.

W163 ML 500, same vibration as the 6.9s at 110km/h and nothing at all in the driveline is remotely similar.

I should also note that the vibration does increase in intensity above 110km/h on the 6.9s but the max legal speed here is 110.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500