Highway Swaying

[EliotW]

1994 E420

I was the on the highway for eight hours thursday, the first half was quite difficult. The car would make sudden leftward drifts with only slight wind conditions. The front end is getting looking at as soon as possible do to steering issues. Is there something in particular I should have checked RE the drifting?

[jbaj007]

rear subframe bushing/mounts.

[Richard Wooldridge]

Improper toe-in front or rear will make the car twitchy. Tires with different tread designs front and rear can make the car practically uncontrollable on some roads, as some tread designs react differently to different road contours. As jbajoo7 said, worn subframe bushings can cause the problem... play in the steering gear or worn components anywhere in the steering can cause handling problems.
Where to start??

[Arthur Dalton]

Most common suspect for that condition on 124 suspension is rear thrust arm links..easy repair with the new, beefed up links..

http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1M30LAGSC1VL0YBFCR&year=1995&make=MB&model=E-420-001&category=L&part=Thrust+Arm

[EliotW]

Originally Posted by Richard Wooldridge

Improper toe-in front or rear will make the car twitchy. Tires with different tread designs front and rear can make the car practically uncontrollable on some roads, as some tread designs react differently to different road contours. As jbajoo7 said, worn subframe bushings can cause the problem... play in the steering gear or worn components anywhere in the steering can cause handling problems.
Where to start??

I think I can rule out the first two, thank you for the suggestions. Appears I have a bit of guesswork and examination to do. I'll borrow my neighbors jacks and inspect the links and bushings in the rear suspension.

Originally Posted by Arthur Dalton

Arthur Dalton Most common suspect for that condition on 124 suspension is rear thrust arm links..easy repair with the new, beefed up links..

Thats inexpensive enough that I might as well go ahead and do it myself regardless. Thanks

Originally Posted by jbaj007

rear subframe bushing/mounts.

Noted

[Arthur Dalton]

< >>

Yes.. that is the recommendation, if not just for the sake of upgrading to the Modified/Heavier links.. the originals were crap and all failed prematurely............

[Paul T]

Hi;the short story is; Following the suggestion of several knowledgeable people, I replaced the one set of links in the rear suspension that are ' the usual suspects', and my problem, which was the rear end of the car swaying side to side, was fixed. The part numbers will be at the end of this post.
LONG VERSION: I bought a 1989 300E with 175,000miles, cheap. I suspect the car had some suspension work done in the past, because the car is reasonably tight. But, it did bounce all over the road, and was not inspiring at 70 MPH. Four new shocks worked wonders, reining in most of the motion (set of Monroes. made in Spain, $280 full set, and I am happy with them). The front end feels rock solid, and does not wander. But one problem remained. AS I came on the gas, or off the gas, the rear end would shift somehow, and cause the car to point in a different direction, requiring compensation with the steering wheel. At speed, this was unsettling. The motion was in the rear, best described as rear end sway. All of the links in the rear, and the differential mounts, and the subframe mounts looked okay. They felt okay to the limited force I could bring to bear on them. But a shop foreman, and a good parts man, both agreed that the diagonal links listed below needed replacing. After doing so, the car tracks 90% better, and tomorrow's 4 wheel alignment should help the rest.

#210 350 33 06, control arm also known as thrust arm, etc.

#210 350 45 06, Bolt kit (nesessary)

#210 352 00 43, sleeve (necessary).

The new control arm is not an exact replacement. A bushing with a smaller ID hole is used. The new arm requires a smaller bolt, with a sleeve to take up the slack where the bolt goes through the bearing carrier.
The biggest dificulty came in getting the replacement bolt to line up upon installation, since the suspension is somewhat pre-loaded. I had to use a hammer handle (correct length) as a wedge between the front of the wheel well, and the suspension, causing the suspension to move aft a half inch, which allowed the bolt to go through.

I also installed 4 new tires previous to the suspension work. I had four totally mismatched tires, but installing 4 new tires made no difference. But my new Bridgestone Potenze G009's are great in the rain.
-Paul T

[t walgamuth]

those links if bad make the car very squirrelley on and off the gas.

if it is all good the 124 is rock steady on its feet on the road.

tom w

[Arthur Dalton]

<<#210 350 33 06, control arm also known as thrust arm, etc.>>

Do not confuse the Control Arm Stays with the Thrust Arms links.. they are two different parts and the Thrust arms I mention are the lower , diagonal arm, not the upper control arms [#210 350 33 06]

[frankbenz]

I might have the same problem with my 1997 E420. I just got it with 130K miles on it, oversized tires 255/45/18".
When I hit road marker (yellow reflective road markers or ceramic bott's dots) while cruising 40 mph or more the car tends to sway left and right and needs corrective streering actions.
Is it oversized tires problem or shocks or what else?
Appreciate any inputs and advices

frank

[EliotW]

Forgot to respond to this one last Fall.

I refreshed the mutli link suspension and while I was at it did the sub frame as well. That resolved the issue.

[stevenstevensteven]

I'm replacing several of my rear end drivers side control arms this weekend and purchased all the necessary replacement bolt kits for each of the arms.

Two quick questions:
1. Do I need to apply any sort of lock-tight on the bolt kit threads during reassembly?
2. Is there any specific torque setting that I should use when tightening the control arm bolts?

On a side note, I found that all new control arm bolt kits all employ a 12mm female 12-point torx head, so I had to find the appropriate male-bit tool to do the job. To my wonder, I found a set of metric 12pt torx head bits at Kragen Auto, which was the last place I thought I would find them. The torx bits use a 13mm hex shaft, so i can either generate torque by using a 13mm wrench or one of my 13mm sockets.

I had found some recommendations to use a T55 Torx head bit, but I understand these are ANSI sizes and also include only 6-point bits. The last thing I wanted to do was strip one of these control arm bolt heads, and the 6pt T55 was just not nearly as snug as the 12mm 12-point bit.

[appatula]

Most of my replacement bolts were pre-applied with loc-tite. I would put a dab of the blue loc-tite on each bolt just to be safe.

I'm not quite sure about the torque specs on the control arms, however, you must technically leave all of these links loose enough so that they settle correctly when the car is let off the jacks, then you must tightened them while the car supports itself. The control arm bolts will just be loosened/tightened again properly when you go for an alignment anyhow.

Also, those 12 pointers go by the name of spline bits or XZN bits.

[stevenstevensteven]

Thanks very much for the help and to the answers.

So, I attempted to replace the driver side Thrust Arms link and found that the replacement arm included a sleeve on one end that extended out the side of the arm such that the sleeve would also slide into and through the mount hole on the knuckle (rear wheel assembly). The problem is that none of the new bolts in the bolt kit would fit in through the ID of the sleeve, as the OD of the bolts are too large. Luckily, the new bolt kit included a shorter sleeve that I was able to insert in the knuckle bolt hole. So, I removed the sleeve from the new Thrust Arm link and installed it using only the shorter sleeve that fit through knuckle bolt hole.

I also replaced the bolts for the Control Arm Stay, again using the shorter sleeve in its matching knuckle bolt hole.

All in all, as both of the older control arms were still in very good shape, it seemed my biggest problem was that the bolt kit sleeves were not installed in the knuckle bolt hole mounts. Doing this removed much if not all of the slop that was creating the movement.

Unfortunately, looking at my lower control arm bushings I realized that those are now definitely due for replacement, but I think I might leave that up to a shop as I don't want to have to deal with compressing the springs. Any input on how much I can expect to pay a responsible shop for removal and replacement of these bushings?

[appatula]

To be perfectly honest, you don't need a spring compressor. I did not tell you this however. I just jack the car up about 12" to 14" then provide another jack under the control arm to support it. Unbolt the control arm on the wheel end and use the jack to lower it CAREFULLY!!! I stress carefully!! Use a heavy duty rope or extension cord and wrap it around the coils just as a safety precaution. The spring will pop out ever so suddenly when you lower the control arm enough with the jack but it works like a charm. I have done this in my driveway about 4 times. If you have any doubts, do not do it. Plan everything out and think about what you will do next ahead of time. When lowering the control arm with the jack be sure you are FAR away from the trajectory of the spring in the case that it did launch out.