Larger bumps in road cause violent steering shake
 

Hey all,

I have a quite concerning issue that I noticed a few days ago. If I am driving over say 40 MPH and I hit a bump in the road like going over a train crossing, the front end and steering wheel shake violently from side to side. It stops when I hit the brakes. Everything under the front end looks OK but I really don't know much about front suspension and steering; especially on MB cars. I am at a loss here. The only thing I know that is not right on the suspension is the nut on the passenger side shock is not tight against the shock mount. It is tight but there is a small gap between the nut and the washer.

Any ideas?

The problem has happened more than once.

I would inspect the Idler Arm Bushing first. It can appear to be ok when static but movement of the steering wheel and the play will be evident.

Another possibility are ball joints which will display a lot of wobble when weight is removed from the front end, such as going over a large bump.

Are you feeling any "knocking" in the area of your feet when going over uneven surfaces, such as a speed bump?

Thanks for your reply SD Blue. The steering feels tight and there is no slop, play or wandering. I don't notice any obvious knocking when I go over a bump but I'll take it out and listen when I go over a bump.

When a similar situation happend to me on other Vehicles is was always something was loose like worn Ball Joints, Tie Rod joints or so on. My other cars did not have Rubber mounted Control Arms so on the Mercedes you have to be included. The Upper control Arms have a tiny Ball Joint on them.

Do you have abnorml pay in your Steering Wheel? If so there is an adjustment for that.

Is there any abnormal Tire Wear?

Basically you need to jack the Car up and do some inspection to find the exact Issue.

Also I removed my Steering Damper over 4 years ago and have been driving with zero issues. So I do not think that would cause issues if it was not working.

Unless parts are disconnected and dragging on the ground, the front end will always "LOOK" ok. Not much special about MBz suspension compared to many others. Inspection will typically require lifting to check for play at each wheel. Grab at 9 and 3 (With respect to an analog clock) and again at 12 and 6. Any play at all, look for where it is coming from. May require a second person to move back and forth slowly and deliberately. Put hand on each joint until you find the play.

To inspect bushings and ball joints you may need a prybar or similar to leverage one part from another. Any play at all is bad.

The wobble you describe is serious. There has to be a component in desperate need of replacement or several that are nearing the end.

Go to a front end shop for a free estimate. Explain you may or may not wish to put money into the car and just want an idea what they could do for you repair wise.

Then decide if you want to tackle it yourself.

Advice: If you have a pro check it out, look it over yourself first, see what you find, then see if they find the same. This could go a long way to building your confidence.

Most repairs you can do yourself, even a basic alignment.

I'm pretty good with fixing most other things but I have not had much experience past replacing brakes, calipers and struts when it comes to front end work. The steering doesn't have any noticeable play in it. The steering wheel is clocked a few degrees off but I'm guessing whoever installed a gasser cluster in my car did that.

I'll check the tires for wear and the wheels for play and let y'all know what I find.

Let me know if you think of anything else to check.

Thanks!

OK, there is some inner wear on the inside of both tires. It's not bad...yet. The car probably needs an alignment. It tracks straight on flat pavement, though.

I didn't notice any clunking or banging when going over bumps or dips in the road during my lunch break trip.

Wheel bearings on the way out can cause what you described. I would take it to a suspension shop as recommended and have them show you what they find.

That's what I thought the first time it happened but then I quickly said no, they would have to be completely shot and I don't have any whirring or grinding noises coming from the wheels. I guess it is possible for the bearings to be bad and not make much noise. Is this something I will find when I jack the car up and test the wheel for play?

They can loosen before completely failing or making noise. Once raised and secured, wobble the top and bottom of the wheel and check for play. Should be little to none. You could also wobble the front and rear of the wheel to check for tie rod issues.

Checking ball joints is a little more involved but can be done at home as well.

Your choice on the Alignment.
A few people have had an Alignment done and a few months later their upper or lower Control Arm Bushing rotted out.
If something needs to be replaced you will be doing another Alignment.

I cant remember if inner Tire Wear is an issue with upper or lower Control Arms.
That info should be below:
Repair Links
http://www.peachparts.com/shopforum/forumdisplay.php?f=82
http://www.peachparts.com/Wikka/DoItYourSelf

I had a friend move the steering wheel side-to-side with the key on, engine off while I looked under the car. There is a clunking sound coming from the driver's side. I noticed a ball joint near the center of the car was moving but the clunking sounded and felt like it was coming from closer to the wheel, maybe even from the upper area. I don't know what the steering components are called but I will have to take pictures when there is more light out. I won't be driving the car anymore until I can get this figured out. It scared the crap out of me on the highway today when it started to wobble for no good reason at 60MPH and didn't want to stop wobbling until about 35MPH. I hope I make it home alive.

OK, I finally got some time during the day last night to check my wheel play. On the driver's side wheel, I got some play in the 3-6 o'clock test. the 6-12 o'clock test showed no play at all. It looks like the ball joint coming off the steering stabilizer is moving before the steering stabilizer does. If I apply more pressure to the test, the stabilizer will move but at that point I am moving the all the gear. Does this result sound plausible? What is that ball joint called so I can order a new one?

Thanks.

http://www.peachparts.com/shopforum/diy-links-parts-category/142397-suspension.html

Here is the 'skinny,' on your question about suspension components and replacement. Its not quite as personal but a little research and you'll have a resources without waiting on answers.

Here's the easiest way to describe it that I can come up with:

Tie Rod - connects to wheel spindle, one joint up and one down, LH and RH

Drag Link - connects LH and RH side, both joints up

Steering Dampner - connects between structure and drag link

Idler Arm - RH pivot point, (mentally picture the steering box on the opposite side of the car, i.e. British) has short Pitman Arm

Is there anyone who can post a picture of the under side of a W126 and point out these components? It's Greek to me, so explaining with words and technical terms gets me confused.

The ball joint I think is bad is on the driver's side of the steering dampener. It is a rather larger one, too. Any links to what this is called so I can buy a replacement?

I checked the passenger side for 3-9 play earlier this evening and boy howdy, was there a lot more play than the driver's side. About 2x as much! It seems like it is all coming from the ball joints attached to the tie rods. Pretty much anything attached to the steering gear box. I should probably replace all the ball joints associated. Does any one know if I can use a standard ball joint tool? I have read about a special tool but I don't know if it applies to these joints. If it does, then please post the part number so I can purchase it. Also, could someone be kind enough to list the part numbers for all the ball joints I need? I might as well do all of them while I have the car out of service. Why don't I see any grease nipples on any of these ball joints? I don't get it.

Thanks for all the help thus far!

All of the Ball Joint struggles are pretty well covered. You can get a Free Rental tool at Autozone and maybe some other places that will take care of busting the Tie Rod type Ball Joints loose.
The Ball Joint on the Steering Knuckle can cause problems getting it loose from the Lower Congtrol Arm and beating it out from the Steering Knuckle.
Best to do some serious reading on that.
You can use a Free Rental C-press from Autozone to Install the Large Ball Joint in the Steering Knuckle but you need to remove the Grease Boot and you need to use it with care as it is not so easy to keep it lined up.

I would go with Lemforder Ball Joints on the Steering Knuckle.
Ball Joints Differences and Tolerances (this is one of my threads)
http://www.peachparts.com/shopforum/showthread.php?t=275392

Repair Links
http://www.peachparts.com/shopforum/forumdisplay.php?f=82

http://www.peachparts.com/Wikka/DoItYourSelf

I found tie rod ball joints but I'm not sure if they are the same for the other components.

LEMFOERDER Ball Joint - Lower - Outer,W0133-1628145 - PeachParts

I also saw that I could buy the whole tie rod assembly for about the same as two ball joints from the same manufacturer. It looks like the tie rod assembly comes with ball joints already pressed in. That would save some headache, right? What are the pros and cons of just buying the whole assembly? Can someone link or list part numbers to any other lower ball joints I should replace (if I can get them out/in)?

Someone else will have to chime in as I do not know much about 126s.

Here is a video I made yesterday evening showing me doing the 3-9 test on the passenger side.

http://www.youtube.com/watch?v=SXIuxbaTCwQ&list=UUX3YyyjeCyrrjETZIhZm95Q&index=1&feature=plcp

A lot of wear present there. It may have been so much that it was advisable to discontinue use of the car. Until at least the worse joints are changed as you did.

Hard to tell how close some of those ball joints are to falling apart. When a previous owner has let things get to this point it is wise to check the whole car over. Obviously if the front end components where ignored what else may have been. Examine the rubber disks on the ends of the driveshaft for fraying etc especially. The timing chain and chain sliders as well. Failure of those items you would not want to deal with either.

The ball joints you linked to in Fastlane are for the Lower Control Arms, not the steering.
From your video, here is what you are looking for:

PeachParts FastLane Mercedes Parts Store

You may be able to replace the tie rod ends but you will need to determine whether it is LH or RH thread. The way to do this is, if you are looking at the end of the rod, clockwise to tighten is RH thread. Keep in mind that replacing both ends of a rod is the same price as replacing the entire tie rod.
PeachParts FastLane Mercedes Parts Store

The best tool is a ball joint separator such as this: (type "universal ball joint separator" in the search box)
TOOL Page (¯`·.¸(¯`·.¸ ZDMAK SPECIAL TOOL STORE ¸.·´¯)¸.·´¯)

Some people will recommend a "pickle fork", but these destroy the rubber so I don't think they are best. The advantage of the ball joint separator is that the joint can be taken apart several times, with no damage. It's a lifetime tool.

1982 300SD like new
 

New upper control arms, new idler arm bushings, new damper arm bracket bushings, new lower control arm bushings, new tie rods, new drag arm, new steering damper, and a MB alignment......you wouldn't believe how nice the difference can be.....!

Thanks Roy, Phil and most especially the forum for the combined knowledge and wisdom that gave me the confidence to tackle this job!

Thanks for all the helpful info, guys.

Here's my plan: Buy all 3 tie rods with ball joints, etc already in them (same price as buying the ends) and buy (possibly rent at AZ?) the separator tool. The next step would be to uninstall my old rods and compare them to the new ones, making length adjustments as best I can to keep alignment close. Install new rods, etc, go to MB dealer for an alignment.

Does this sound like the path to take?

You might as well replace everything to be safe. I had to put about $800 in parts into mine when i got it, but now the front suspension is like new, rather than being so loose its scary to drive. Its not that difficult to do really.

It would be ideal to replace all steering and suspension components, install new wheel bearings, etc but I just don't have that kind of money to throw into an $850 car. At least not all at once. After this job, I think it will be good for a little while.

I am dreading the steering knuckle ball joint replacement. It looks like a royal PITA.

PITA
 

Based upon my recent experience, I recommend that you replace the idler arm bushings first, then the tie rods / steering damper and drag rod. If you still have a few dollars, take a look at the upper control arms. If your budget holds, and your inner demon needs a workout, replace the damper rod bushings. Then go to the MB dealership and get your ride aligned.

But thats based upon exactly 1 time to this particular 1982 MB 300SD rodeo!

Idler arm repair kit.

http://catalog.peachparts.com/item.wws?sku=W0133-1629430&itempk=77412&mfr=Febi&weight=1.35

Should I grab one of these as well? Is this the correct item?
I guess I should get the steering dampener while I'm at it.

It didn't appear bad in your video. However, if a visual inspection reveals oil saturated rubber, it probably wont be long.

Another item that probably needs to be addressed is how oil saturated the tie rod ends in that area. A likely suspect is the turbo drain grommet. This is an inexpensive repair and may be an easy task if not to dry rotted. It also has an added benefit of lowering oil consumption.

You are exactly right. I have a leaky turbo oil drain. I have a grommet sitting in my virtual shopping cart on fastlane.com along with all the other parts. It doesn't leak too bad but I still get a few drops here and there. It will be fixed at the same time the new steering parts go on so I do not continue damaging boots and seals from oil saturation.

I got the shipment of parts. I'll start installing them tonight. Is there a torque spec on the tie rod end clamp or should I just use German specs?

That is a threaded end so all the clamp needs is just enough to keep it from falling off.

Is there a spec for the tie rod ends to the wheel? They weren't on too tight. I busted them loose with my 3/8" ratchet pretty easily.

I got the parts installed and the car aligned. Seems OK now. I still need to drive it some more to be sure but I think I am in the clear as far as my original shaking concern goes.

Thanks for all the help, fellas!

I got all the tie rods and steering dampener installed over a week ago. I got an alignment at one of the big tire retailers. MB wanted over $200 to do it.

I am noticing/have noticed a clunk as soon as I apply the brakes. I also get clunks and pops when accelerating or on large rolling bumps. I'll have to search the site or start a new thread for that crap.

It might be your Guid Rod Mounts clunking.

PeachPartsWiki: Suspension Bearing Bracket guide rod mount replacement

Charlie

Oh, geez! If Whunter dreads this job, I am screwed. How dangerous is it to drive the car in the condition it is in? I have to drive the car until I finish the turbo installation in the truck.

Any part of the suspension that is worn will usually place undue stress on other parts. Worn guide rod mounts will give abnormal tire wear but the main factor is diminished control when braking. Which is one of those things that, in a severe situation, might be critical. It's your call, I'm just pointing out the apparent risks.

The guide rod mounts aren't that bad, especially since you aren't dealing with the rust issues that WHunter faces in Michigan.

Place the front end on ramps (which provides weight on the front wheels). I used a come-along to hold the suspension in place, front to rear, which helps in reinstallation of the bearing bracket bolts. Measure the threaded portion of the guide rod mounts to maintain your alignment. Unbolt the bearing bracket and remove the guide rod mounts.