1987 TDT keeps breaking sway bar brackets
 

I will try again, Hi, I have a 1987 300TDT W124.193 that is about driving me nuts.
I cannot seem to keep sway bar brackets on the thing.
I have had the brackets break....well let me see, five times by now.
I have replaced them with "new" updated brackets, still break.
I have tried installing jacked up with wheels off the ground and sitting on the ground with weight on the car.
They are not to tight as the bar will spin inside the rubber bushings which are also new.
I have even put new coils in the car and still today the bracket breaks again.
I cannot figure it out, their is no reason for this I can see.
Anyone ever hear of this before?

Can you post a picture of the broken bracket(s)?




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I suppose, but they break where the c clamp bolts to the bracket over the sway bar. It is almost like they are being torn apart from downward pressure

Is this a continuation of this problem?

http://www.peachparts.com/shopforum/diesel-discussion/267816-sway-bar-troubles.html

Charlie

Yes it is, That was before I installed new "updated" brackets. So now I am even more puzzled as I thought that was it.

One of The brackets on my TD pulled off at one of the bolt holes. Being a cheapskate I just used the mig to repair it by welding a washer on to the C clamp. It has been bounced over some very rough tracks since then & not broken again.
Is it the side that is on the road edge side (right hand for you)?

My passenger side bracket broke about six months ago. We had an extremely short steep driveway at the time. I used to get going fast enough to coast up it, so I just assumed that was why it broke. There was a downhill slope before the driveway so when the car first started up, it twisted the front end. I guess I'll take a look at the new one and see how it is holding up. We have a nice flat driveway now so I suspect they are both fine.

The last time I was in Nova Scotia it was flat. Do you have an unusually steep driveway or live on a dirt road with huge pot holes?

Have you replaced the rubber bushings on the sway bar?

I live in the Valley, nice and flat. Good driveway. I have replaced the bushings and that is actually when it all started. I have had both sides break at different times. This time it was the passenger. Most times it is the passenger side but I believe the drivers has broke once out of the four or five times. Before I replaced the brackets I did weld them up and re-enforced them with a piece of steel and it still broke.

Is there anyway the you could double bracket them? IE put one on top and bolt them together? or well they not sit together nice and tight?

Just a thought.

Charlie

Probably not work as they are not meant to fit together. But there must be a reason they break.

Can you take some pictures of your front end from underneath? I'm wondering if something is different with your car. I still have my belly pans off from a recent transmission fluid change. I'll take a look under mine when I put the pans back on.

Have you tried putting a bit of grease on the bar before installing the bush ? the rubber may be grabbing on the bar.

could the orientation of the sway bar be an issue? like left-to-right mounting? i have not really looked at my sway bar but i figure if the swaybar isn't "flat" it may be an issue. like having excess pressure/tension on the brackets... is the front "stance" normal?

i stumbled upon your thread regarding the same issue... i'm pretty sure mounting the sway bar wheels up and whatever is a non issue... as long as both wheels are level... people saying otherwise do not understand what the bar actually does. every time both wheels are level there is absolutely no torsion/ tension on the bar and anywhere else. once the wheels aren't level with each other that's the only time the sway bar experiences any tension/torsion. the brackets are just there to "guide" the swaybar... so it doesn't fall off or veer away when torsion is applied.
if there is a difference when the bar is upside-down or right side-up i'm betting my money that the sway bar is mounted upside down. causing unnecessary downward tension on the brackets with every bounce.

That sounds like a reasonable theory, since it started right after he replaced the bushings.

I have thought of that, but it will only mount one way. It will not fit upside down as it will hit the oil pan. I do agree with you on it not mattering of where the wheels are. The bar turns inside the bushings so it should not matter where the suspension is. Yes I greased the bushings and I can attach the bar at the front and turn it by hand inside the bushings. I am pretty mechanically inclined however this is a mystery, there is no reason it should break those brackets.

Why are we still talking about this without pictures to look at ?

Good question.:confused:

I can take pictures but I am not sure how it would help. It's a broken bracket. broke off clean where the top bolt goes through.

what about the bushings/mounts at both ends...the ones on the control arms... could they have been mounted incorrectly? though i do not see how... took a quick peek. maybe they're not allowing the sway arm to pivot?... dunno... just throwing it out there

I thought of that too. They are on properly, only go one way. The sway bar is larger diameter in the center so it would be impossible to install wrong. I also have tightened up the center and I can pivot by hand.

Look, both threads you started have multiple requests for pictures. you have replied several times that you can take pics. do it! something is wrong with your car, and all the words you can type are useless unless we get information you are not capable of providing in words.
do you have access to a lift? if so, get it up on one, take off the wheels, and photgraph the entire underside of the area. take pics of the driver's side including all moving parts, and the passenger's side. I'd like to see if you have out of place parts in there.
the 124 is known to have weak mount points and control arm failures. lets get pics.
lets get pics. lets get pics. lets get pics...

X2,X3,X4..............

Wow, just stumbled over this thread, and I have gone through 2 stabilizer bracket breakages since I bought the car in Dec2009. I do have a rough road nearby that periodically has bottomless potholes, but the car normally has such a capable confident feel that you think nothing can faze it, and then another bracket bites the dust! It breaks just above where the bracket clamps around the anti-roll bar. I have repaired it a couple of times and replaced the parts when they come in but so far my repaired parts have survived better than the new parts.
My theory so far is that the brackets have to bend in normal operation due to the suspension geometry, and over time the material used in replacement parts has changed towards less cost. I'm guessing they should be a spring steel and the new replacements I bought certainly are not. The search for the perfect bracket continues!! (and I will try and post pics but home reno currently takes precedence)
Bernie in LaHave NS
1994 E300 TurboDiesel Wagon 124193 603960

You have a really amazing mystery.... lots of people are trying to help you....
I am glad you are not in charge of any aircraft crash investigations...
Little things count in terms of figuring out how and why something broke...
closeup pics of the bracket may show from which direction the breaking force was applied.
It is just silly to keep jawing about this without pictures... and vstech described what you need to do..

We are going to need to see pictures of your car as well. Did Canada get diesel wagons in '94 or was it imported privately.

My wagon is an 87, The bracket breaks in the same place. I have been a little tardy on posting picture as my wife is gone when I get up and when I get home. Weekends busy just seem to forget about it, but I will get a couple pictures. The new brackets lasted no more than a month or two.

LOL, it has been 6 MONTHS since the first thread appeared... and people asked in that one about pictures...

Which begs the questions; why was a second thread started and why didn't the mods merge these two when the second one was started?

has it been that long?

The first post in the thread was on 12/20/2009 so yes it has been that long.

The first request for pictures was on 2/28/2010 so that was only a little over 4 months ago.

See why it's easier to keep it in one thread?;)

It does appear that a few people are very very keen to see pictures so here's one of the broken brackets.
My car was built in Germany for the Japanese market, curiously it is LHD, and was imported to Canada in 2009. It has about 120,000kms on it, does 40mpcanadiangallon, and runs beautifully (apart from the occasional broken bracket!):)

Right across the bolt hole..
You might want to look in the parts manual...
or even if not shown there.... place a grade eight washer under the bolt...
Can you lay it on a scanner and send that scan ?
Or get really close up with the camera in good light ?

What exactly attaches to the other end of that bracket ?
Could unwanted movement there cause this to break.... at the point where the bolt will not let the upper part of the bracket move ?

i have a theory... maybe the bolt head was just a tad too big and was propped up against the curve of the bracket and was pushing down on it. soooo, tightening was enough to give it undue stress at that point... which eventually caused the failure...

from the marks it seems the bolt was tightened up real good... since there is a rubber bushing in there maybe its a bad idea to overtighten anyway...

AFAIK, tiny fractures DO cause bigger fractures when it comes to metals...

still doesn't explain the breakage above the bolt hole though... (c holmes')

speaking of overtightening... can the angle of the bracket be altered(pivoted) off axis when tightening(overtightening) the lower bolts for the swaybar? imagine the swaybar bracket...angled not perfectly perpendicular to the pushing force of the swaybar, negating any "flex" that the flat part has to offer... something's gotta snap right?

Question
 

Have you inspected the spring and perch on both sides?

W210 DANGEROUS FLAW please read (crosslinked in post #1 to all on topic data)
http://www.peachparts.com/shopforum/bodywork-repair-paint-tools-tips-tricks/147997-w210-dangerous-flaw-please-read-crosslinked-post-1-all-topic-data.html

W124 SPRING PERCH = Front Spring Bracing


Have a great day.

I gotta agree with Whunter here, that is a stress break, and it's on the bolt hole, so the two ends of the bracket are pivoting. something on your bracket is moving! if you can get the car up on a lift, and get some pictures of the underside I may be able to assist your diagnosis. if not, eventually I will have my 87TD on a lift and I can see what could be causing it to stress fail.
look carefully at the picture. you will see wear marks on one side of the bolt hole from the bolt head, but none on the other! it's moving!

How about only one end moving ?
that is a long torque arm on the section not between the two holes bracketing the grommet which holds the sway bar...
What does that attach to way off down there ?

the long end is free from movement marks, my bet is the short end is moving.

So describe the way that part can move with a solid rubber grommet and a sway bar inside it.....
BUT that other ' handle' ...whatever it is attached to... if that moves then the break happens exactly where the working part of the bracket is secured to the firewall....
Show me those ' movement ' marks and why they could not have been produced by the movement of the long arm....

that's why I want pictures on the car... I have no idea how it attaches to the car or what could move. just that one side of the broken part has marks all over it from the bolt head, and the other side does not.

Absolutely! This is what we all been waiting for. Sheesh!!!!






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Not sure if this will help, but here goes.

I just saw a w124 today and wished I had a camera to take some pictures. But I have say that is one "F"ed up design that Mercedes decided to choose.

The bracket just hangs down like an upside down "L" and the swaybar attaches to the end. No body attachment except at the top. Not much strength there and I can see how it would crack in half at the bolt holes. Your better off creating some new units out of some pipe stock.



http://www.peachparts.com/shopforum/...3&d=1278968443




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Ok,,,what the heck does 38 and 41 go in to ?
The battery box ?

#41 bolts into a captive thread in the chassis.
I do have another theory for C Holmes: Bracket 14 is smaller than bracket 50, and assembling using 14 instead of 50 will prevent the clamp from fully closing, and accelerate fatigue in the bracket35. (Don't ask me how I know!)
Leathermang's suggestion to put a washer under the top bolt53 (there are 2 bolts 53, the parts picture is not very clear on that area.) is a good one, as it would spread the load and support the bolthole.
Brackets 35 and 50 must be bolted together solidly, no gaps.

HOLY!!!
no wonder that thing is breaking! wow, what a poor design!
I TOTALLY see how the thing would be twisting! now, how can we fix it?
I'll get under my wagon tomorrow and see what I can see. that thing really needs some triangles in the support design!

Poor design? Based on your finite-element modal analysis? Pardon my scepticism.

It works, on a million 124s, but this one fails. I'd say that the evidence points to something flawed in this car, not the design.

The loading on the bar at the bracket, by design, is vertical. The top of the bracket is connected to the frame tips.

Did you get brackets and grommets for the 124 wagon or sedan? I measured the swaybar diameter on my '87 wagon, it is significantly thicker than on my '95 sedan. Seems that putting sedan hardware (smaller dia) on a wagon swaybar might cause stress in the mount. Also, if the bushing were clamped tighter (wrong bushing or clamp) than the design, rotation of the bar in the bushing would cause the bracket to stress at the top bolt-hole instead of allowing the bar to rotate in the bushing (which appears to be the design).

I don't have access to a part breakdown, is the wagon swaybar hardware a different part number than what you have received/installed? Different than the sedan?

What are ' frame tips ' ?

There is a subframe that supports the engine, the ends/tips of those frame members is where the swaybar mount hangs.

Online EPC shows different numbers for the swaybar and bushing on 300TD vs. 300E. It was late last night and I don't remember about the bracket. But I'd say that's enough for the OP to call a qualified parts person and make sure they get the right stuff. And if they don't know the full history of the car, then taking a measurement of the torsion bar (MB's term) would be in order since an incorrect part may have been installed in the past.