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Torsion Bar

2861 Views 12 Replies 10 Participants Last post by  goofyguy
I broke the torsion bar where it connects to the upper control arm. The end of it, where the bolt went broke off. Looked all arownd, but can't find it for sale. Is it not avaliable or what?
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Hi Veece,

I think you are referring to the front sway bar(?) pictured below.

I hope that is not the case, as the replacement will be time consuming at the very, very least. If that is the part that has failed, a replacement from a breakers yard is in order, preferably one in California or Arizona. The reason I say that is I was told that mine potentially could fracture when the upper control arm was replaced last Summer. Apparently, they tend to fail due to salt corrosion........

Good luck, I'll stay tuned. MBL

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Veece,

I really don't mean to bring bad news, but I was quoted the astronomical price of $4K to replace it with a new one at the MB dealer. Unlike many other makes, this bar (I'm sure you have checked it out by now) crosses above & behind the engine and below the brake booster. As explained to me, it is major surgery: A/C, heater lines, electrics, removal of the brake booster..............[xx(][xx(]

Last Summer, I did an internet search to see if the dealership was telling me the truth, as I'd never heard of a sway bar rotting out. I found it does happen, and it is most apt to fail in a northern locale where there is a lot of snow & salt treatment on the roads.

Having taken a closer look at the cross section of the upper control arm/sway bar connection, it is so apparent just how thin the s/bar is where the bolt threads in.

Sorry man, MBL
Thanks for the info. It was the end part where the bolt connected, it had rusted away. I just welded on a bolt to the end and put bushings on as a temporary fix. I'll have to look for a different one sometime though. Thanks again
5
Here's how to fix this. You have the part made, measure the exact distance, and cut off with a zip cutblade on a 5" grinder. You clean up the shaft, install the new part, pull back about 2 mm and dimple drill where the holes for the screws are. The reason you do this is to secure the replacement in place and then it pulls the new stub tight to the cutoff. You coat the cutoff shaft with loctite bearing mount and set screw in place, then lock the nuts in place. I designed this and repaired mine 2 seasons ago and it is fine. I have more pictures and information if you like.
Iain

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Hi Thguns,

Nice creative work you did. I'll bet this kind of failure will become more prevelant as our cars age.

I'm wondering if a preventative action could be taken to prevent this occurance. Then I think one could easily fracture a weakened/rusted 'bar just by attempting disassembly for the purpose of inspection....

Hmmmmmm, MBL
I had this exact repair done to my car about 8 months ago. It scared the hell out of me the first time I looked into the engine bay. When it was all said and done, I had spent almost $1,000. $700 just for the labor alone. 16 hours is what the book says, but I think that it was more than that because some of those parts put up a fight. Good luck with you repair, and take picture(I forgot) so that you can justify to yourself and to your wallet why this repair was so costly.

ps...if there is anything else that you can replace at that time while the suspension is free...Fix it now.

Again...good luck
The front sway bar on the 1985 500SEL failed in exactly the way you described. Did you happen to make an extra repair part? If so, may I purchase it? Otherwise I'll take the drawing to a local machine shop. Thanks. [email protected]
what a great solution to a pain in the arse problem.
Torsion (Sway Bar) Repair W126

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I have a 1987 420 SEL that has a bunch of miles (as in over 300K). I bought it cheap and found out why when I tried to change the upper forward sway arm bushings. Guess what? The right side broke and the left side darn near did. I am an old (well not that old) aircraft mechanic and don't give up easily. After several bad words and a little research, I came up with a repair also. It copies the before mentioned repairs to some extent, except I simplified it considerably.

The long and short of it, I may post a detailed repair at a later date, if I see any future interest.

Good luck and I would suggest being ready to make this repair, or ready to take it to a shop before attempting the bushing replacement. The dirty atmosphere of the wheel well is an excellent place for oxidation (rust) of the metal under the bushing, and the internally threaded thin piece of rusted metal can easily break.

I still need to do the left side. It has slop in it, due to the void between the bushing and rusted bushing mount. This will cause the frontend to feel like it is loose and sounds pretty bad - like a loose clunk or thud - that's airplane talk for something not being right.

Anyway, I made this repair on the right side yesterday and it helped considerably. I will make the left side repair later and have the car aligned to see if everything is good.


Additionally, my repair does not have any internal threads, instead I had the repair piece made solid with external threads at the forward end for the bushing.

More later (maybe) - Ken.
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Torsion (Sway Bar) Repair W126

--------------------------------------------------------------------------------

I have a 1987 420 SEL that has a bunch of miles (as in over 300K). I bought it cheap and found out why when I tried to change the upper forward sway arm bushings. Guess what? The right side broke and the left side darn near did. I am an old (well not that old) aircraft mechanic and don't give up easily. After several bad words and a little research, I came up with a repair also. It copies the before mentioned repairs to some extent, except I simplified it considerably.

The long and short of it, I may post a detailed repair at a later date, if I see any future interest.

Good luck and I would suggest being ready to make this repair, or ready to take it to a shop before attempting the bushing replacement. The dirty atmosphere of the wheel well is an excellent place for oxidation (rust) of the metal under the bushing, and the internally threaded thin piece of rusted metal can easily break.

I still need to do the left side. It has slop in it, due to the void between the bushing and rusted bushing mount. This will cause the frontend to feel like it is loose and sounds pretty bad - like a loose clunk or thud - that's airplane talk for something not being right.

Anyway, I made this repair on the right side yesterday and it helped considerably. I will make the left side repair later and have the car aligned to see if everything is good.


Additionally, my repair does not have any internal threads, instead I had the repair piece made solid with external threads at the forward end for the bushing.

More later (maybe) - Ken.
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Welcome, to take advantage of all the forum features, please re visit the 'Welcome to the Forum' tutorial sticky on top of the W126 page, as well as the two DIY stickies.
It will show how to search the forum (3 words min.), and even has a link to the Russian MB site where you can run a VIN#. The forum archive has a wealth of information.
Cheers

Please complete your profile with a location by clicking on 'user CP' above.
Mercedes Benz produced country specific versions of our cars, and it makes it easier to offer advice.

P.S. Scroll all the way down to the help forum, it has a sticky on posting pictures.
Here's a repair option:

MercedesShop Special Tools
Swaybar repair

Baum Tools sells a kit where you chop the end off the front swaybar and weld their piece on.
R&R of a front swaybar on one of these cars is a SERIOUS investment of time...
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