Torsion bar salvageable? - PeachParts Mercedes-Benz Forum

Fulcrum525 · #1 04-09-2018, 10:07 PM

I've had a front end wobble for some months now and have been waiting for spring weather to do a full front end rebuild. Today on the way home however I finally heard a "thunk" from the front and and instantly noticed I pull to the right under braking. I knew instantly that something broke. Thankfully it was close to home so I took it slow. Looks like the end of the torsion bar that connections to the upper control arm. I don't know what the end looks like normally to know if it still usable when I do the rebuild or if i'll have to use this saver. Mercedes Special Tools

https://imgur.com/a/2CBtF

andrewjtx · #2 04-09-2018, 10:49 PM

Your only options are to get the stabilizer bar end repair kit. $150. QP1000 or replace the bar. Unless you have plans to pull the motor, you're not going to replace the bar.

BillGrissom · #3 04-09-2018, 11:46 PM

The end repair should be fairly easy to weld. If you don't have one, you could buy the Harbor Freight $90 wire-feed welder which has worked well for me. Buy a grinder too to make the welds purty. Many shops could weld it for you easily, if you prep it and tow the car to them. If smart, they would have you sign a liability waiver.

Junkman · #4 04-13-2018, 05:28 PM

I didn't see anything about removing the engine. What about the one on your parts car? Perhaps find out whether it is strong enough for the diesel.

leathermang · #5 04-13-2018, 06:31 PM

The Torsion bar is a Spring
you can't just weld on it without doing proper heat treating afterwards.
A Torsion bar only works in corners.
it will not cause a ' wobbling' driving along in a straight line
and should NOT cause your car to pull either direction in braking..
you have something IN addition to the end of the torsion bar which needs fixing.

maceo1973 · #6 04-14-2018, 10:53 AM

Had the same problem on my '84 300CD about 8 years ago.

I ended up using the torsion bar saver method, I think it was around $100.

Although I did remove the torsion bar in order to have the ends prepped and welded on.

It's nowhere near a 20 hour job to remove the bar as it states in the advert. As far as I can remember you need to remove the battery tray, throttle linkages, couple of coolant pipes at the back of the engine and possibly the brake booster, then manipulate it out.

The welded ends definitely worked for me, really easy if you can get them welded on without taking the bar off.

That was for a W123, the 126 may be more difficult to remove the bar.

Diesel911 · #7 04-14-2018, 12:13 PM

The kit is for a W123 or W126.

In the repair links there is are threads on using the kit and the another repair.

Fast navigation Fast navigation Do It Yourself Links

The other repair requires you do drill a hole down the center and thread the inside of the hole for a bolt.
The Torison Bar is a spring but the Repair Kit has been used for years and years with no issues anyone has posted. However you need to cut off I believe it was one inch of the end of the bar. However, better to read the threads.

I removed the brake booster in order to get at the drivers side rubber bushing at the fire wall.

On a W123 you can remove the Swaybar but you need to remove stuff like the Brake Booster. If you are doing a compete front end rebuild there is also 2 rubber Bushings where the Sway Bar is clamped to the lower fire wall.

Diesel911 · #8 04-14-2018, 12:32 PM

In the factory service manual section 32-300 deals with removing a Torsion Bar from a W123.

There no pics of the bar itself but what is not normally scene is that there is plastic covers above the Bar and when those covers are removed the whole the bar goes though is larger.

After everything is disconnected from the Bar and all of the stuff including the Brake Booster and heater hoses are removed that would prevent the Bar from being pulled straight up is removed the ends of the bar are pointed down and some how you can maneuver the bar around and pull it up and out of the Car.

When I changed the sway bar bushings at the fire wall I found I had rust and holes in one of the areas and also below the Batter Tray (that also needs removal to get out the sway bar).

Having the Sway Bar out of the car would make it easier to saw and have welded.

resto108 · #9 04-16-2018, 01:10 PM

"A Torsion bar only works in corners.
it will not cause a ' wobbling' driving along in a straight line
and should NOT cause your car to pull either direction in braking.."

What locates the outer end of the upper control arm if its not the sway bar?

leathermang · #10 04-16-2018, 02:30 PM

Quote:

Originally Posted by resto108

"A Torsion bar only works in corners.
it will not cause a ' wobbling' driving along in a straight line
and should NOT cause your car to pull either direction in braking.."

What locates the outer end of the upper control arm if its not the sway bar?

While the sway bar helps ' locate' along with the two lower control arm bushings , the on upper control arm bushing AND the ' control rod' ( which extends directly to the rear and is held by a elaborate bearing ) .... that does not mean it has any function OTHER than reacting to what the suspension on the OTHER side of the car is doing... It used to be called an ' anti roll bar '...

page 33.3-200/4 Service manual , Chassis and Body , Series 123, Volume 1
has the only reasonable picture of their relationships I could find.

Ok... they are calling it a Guide Rod in this video.... it controls forward and rear movement of the wheel due to braking reaction...

https://www.youtube.com/watch?v=KgykGUUmy6c

Diesel911 · #11 04-16-2018, 06:29 PM

The Torison Bar also keeps the Upper Control Arm from goingong forward and backwards and forces the Upper Conrol Armo to follow the arch of the Sway Bar movement when the Upper Control Arm goes up and down.

The Upper Control arm being moved forward and bacwards causes the Caster to Change and when Caster is changed there is also some change in the Chamber.

Remember the Upper Control Arm is mouted on a Rubber Bushing and it can be flex around if there is enough force to do that.

leathermang · #12 04-16-2018, 06:34 PM

Quote:

Originally Posted by Diesel911

The Torison Bar also keeps the Upper Control Arm from goingong forward and backwards and forces the Upper Conrol Armo to follow the arch of the Sway Bar movement when the Upper Control Arm goes up and down.

The Upper Control arm being moved forward and bacwards causes the Caster to Change and when Caster is changed there is also some change in the Chamber.

Remember the Upper Control Arm is mouted on a Rubber Bushing and it can be flex around if there is enough force to do that.

Then what is that straight bar running parallel with the center line of the car.. with the serious Bearings do ? Which used to be called a Control Rod...

leathermang · #13 04-16-2018, 06:45 PM

HERE it is called a Strut Rod...
The design of the bushings which hold the Sway bar are not sufficient to provide the function you attribute to it... and it is a Spring...

That for / aft control is provided by a solid rod with serious bearings on its end..

https://i.pinimg.com/736x/5e/96/26/5e96262382112bf6624d5a8b880e11b8--diy-car-car-repair.jpg

Frank Reiner · #14 04-16-2018, 09:21 PM

Greg:

This link shows the correct suspension diagram for the thread. The "sway bar" #14 (aka, torsion bar) is a part in the upper suspension. The strut rod (Control Rod) is a part in the lower suspension.

https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRMJ5YhulGunNhU6_Pi7Wk4c0f3f-eelHkWfA2CieJVaYddTrA8VA

leathermang · #15 04-16-2018, 11:17 PM

Thanks Frank,
That is correct....and I have a good picture from the FSM showing the considerable bearing at the end of our Control Rods where they attach to the chassis... but I can not get it to upload from my desktop.

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