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Gray Market Survivor 08-21-2001 08:22 PM

Front Suspension Question W123
 
Folks,

Getting on the highway tonight I heard a loud clunk under my car. I thought I hit something, but I didn't see anything in the road. I thought nothing of it until I was getting off the highway 50 miles later and braking. It felt like I had a flat tire and as I turned the corner, it felt as if my front right wheel was going to come off. I thought it was a flat tire. No such luck. It turns out that my sway bar came out of the upper control arm. I regard this as "highly unusual," especially since I just had the left and right lower control arm bushings replaced as well as left and right strut rod bushings and track rod mounts 800 miles ago. Ever since I got the car back from my mechanic, I heard a strange rattle in the front end when I turned the engine off and couldn't quite figure out what it was. I assume it was the loose bolt on the sway bar.

I had the entire right upper control arm replaced 10k miles ago as well as three ball joints replaced by my dealer, bud had no problems with it. I never noticed any loose rattles in the front end.

I examined the sway bar end and it does not appear to be rusted out and the threads look good inside.

My question is:

Was it necessary for my last mechanic to loosen the right upper sway bar in attempts to replace the lower control arm bushings, strud rods, and track mounts? or doing the alignment?

Would it be more likely that the entire right upper control arm, when replaced, did not have the sway bar tightened to it?

I am leaning towards the last mechanic forgetting to tighten something, but I am open to other suggestions.

I feel as if I could have been in a major accident because of this and I would like to know why. It was my first time at both the dealer who replaced the right upper control arm and the shop that did all the other suspension work. My left sway bar is just fine and nothing has ever been done to it. I don't think 271k miles is too much for a sway bar. Am I being too hard on the shops I have taken it too?

Please let me know your thoughts, cause I'm a little shaken.

Thanks,

:o

stevebfl 08-21-2001 09:07 PM

I see no reason to blame the tech who did the alignment and lower control arm. If you must draw conclusions, I must say that the person who installed the upper control arm is the logical choice.

As a technician I find it very interesting that you tend to blame the last person you saw rather than the obvious installer of said loose part.

You can't imagine the stereotype customers this brings to mind.

Gray Market Survivor 08-21-2001 09:36 PM

What?
 
Steve,

Thank you for your response, but I consider myself to be quite understanding. I am human, just like the techs who service my vehicle. Don't worry, I don't want punitive damages. :) Perhaps I am just a little frustrated after putting $4000 dollars in parts and labor these past six months ($1800 in front suspension) and having a front suspension failure. I just want to know why things may have happened so I can avoid disaster in the future. I am not on a witch hunt, just a safety imovement opportunity.

The reason why I question the last person who did my alignment and other work is because the rattle when I shut the engine off began immediately after I left the last shop. Hindsight tells me I shouldn't have been too shy and brought the car back to be looked over.

Don't you think it is an incredible coincidence that a part that was put on 10k miles ago would suddenly fall off just after another job on the front suspension? This is why I want to know if the sway bar is loosened in the alignment, replacing of lower control arm bushings, or strut rods?

I assume from your answer that it is not.

stevebfl 08-22-2001 08:12 AM

Not only would it not be involved, but under an alignment lift it is very hard to see the upper control arm.

I believe a proper alignment starts with a diagnostic road test and proceeds to a inspection for loose links. If the noise was apparant then it should have been checked before alignment. If it wasn't regular or if it sounded like an engine or exhaust rattle, it might not get pursued. It would not be something I would normally look at. They never come apart there and the bushing causes no problems.

I just did an alignment yesterday for a body shop. I found bolts loose where I needed to operate so I checked all of them. They had left 3 nuts loose.

There is one of the longest posts ever running right now on the iATN (International Autotomotive Technicians Network). The story goes that a recently serviced car has one of its wheels fall off while the vehicle is pulling a boat while on vacation. The shop owner is terribly embarassed and is asking in what manner to fire his young (valuably, inhouse, trained) technician.

The posts go from "have you never made an error" to "what shop proceedures were lacking that either caused this mistake or caused the tech to be in a rush" to "are you sure you aren't being scammed - with proceedures to tell if the broken lugs were from overloading or being left loose.

Only one post said to make sure the shop owner kept the tech long enough to pay off the repairs and then fire him. Most agreed that the risk was a shop function and unless business profits were shared, the cost of risks should not. (I agree with this).

I discuss all this because, as most respondents in the post, I have had two wheels come off because of my techs and about 3 oil plugs left loose (luckily no motor damage- knock on wood) over the thirty years I have managed others labors. Good lord willing, I will live long enough for a few more.

Two conflicting goals contribute to this problem from a systematic approach. First is the techs desire to make a living and second is the car owners desire to retain as much cash as the problem will allow. If the shop is honest they probably don't make much and struggle to perform to keep cost down. Flat rate pay systems throw all the burden for performance (billed hours not necessarily cars fixed) onto the tech. Hourly or salaried techs are less likely to be in these positions. Think about the other technicians in related fields like airplane techs, heavy truck techs, railroad techs, etc., they are never paid by piece work. They are paid a real wage and then go to work. There are no end of the month mortgage to be paid, pressures on that jet mechanic to get that engine bolted in before the pay week ends.

Think about it. Auto repair could be a lot better if it was done with an open checkbook like health care.

LarryBible 08-22-2001 02:40 PM

Steve,

Thanks a bunch for your insight. It's always intriguing to read.

Yes, I have seen a drain plug left untightened by one of the most impressive truck mechanics I ever knew. He was a salaried tech in a large major brand truck shop. I had just gotten out of the army and was a service writer there part of the time I was in college. This was thirty years ago and I don't remember how much the repair cost was, but it was probably a few weeks pay or more. He really felt terrible about it, but things happen. I saw him really working even extra hard after that in an effort to make it up to the shop.

He developed a habit from the experience that I learned from him and still use today. After that he never (and I have never) threaded in a drain plug without the wrench for it in his other hand. This way if he was called away for any reason, he could tighten it before leaving.

Even as absent minded as I am, this has worked for me for thirty years so far. Of course, I don't work in a shop for a living, so I have had relatively few chances to make this mistake.

The pro techs are human, the best of them will make mistakes.

Thanks again for your insight,


Gray Market Survivor,

From your description, I expect that if the truth could be known, the first tech that replaced the upper control arm lightly snugged the bolt on the sway bar and it coincidentally started rattling and them came out after the lower control arm job.

I hope I don't sound condescending or anything when I say that you should have investigated the noise immediately after hearing it. We all learn this kind of thing sooner or later, and in my case I probably have even been guilty of such a thing even after learning it earlier.

BTW, I'm quite envious of your 5 speed 300D. The ones sent to the US gave us the extra cylinder but made us take the automatic transmission which robbed the extra torque from us.

Best of luck,

Gray Market Survivor 08-22-2001 10:28 PM

Lesson Learned
 
Thank you Larry and Steve for your posts. I guess after I calmed down and spent a little time under my car, I pieced together what happened.

My hunch was it was the dealer's mechanic that is at fault, but perhaps not for not snugging up the bolt.

As I mentioned, the dealer replaced my right upper control arm. I specifically told them to replace any rubber that needed replacing because I hadn't been able to align the car after two previous shops.

8,000 miles after I the dealer, I still saw uneven wear on my front tires so I was thinking of trying to sell her. Low an behold, I started a new job near Akron and a great local shop was recommended by a friend. They only work on German autos, it is 4th generation shop, and their place is spotless. After finding this shop, I decided to have my car aligned once again with all necessary parts. The new shop did lower control arm bushings, strut rod mounts, and strut rods, right rear half shaft (fuel tank leaked on rubber and cracked boot) and motor mounts. It ran like new after I left the shop and I felt satisfied.

Oh yes, my point: I lost the bolt out of the sway bar and the washer combination while I was driving, but I still had the aft bushing in place and it was worn down to the nub. I can only assume the forward bushing was the same way. I am theorizing that due to normal wear and tear, there was not enough force on the bolt and rattled its way out or the previous MB Tech did not use Loctite. I noticed the new bolt came with a locking compound pre-applied to the threads.

I am a little miffed that while MB dealer did their $1100 alignment and removed the sway bar to install a new upper control arm, they didn't replace (2) $4 bushings and a $3 bolt or they reused a blot. My service CD-ROM must be riddled 10,000 times with that little note not to reuse bolts on principal! I know for sure the bushings weren't replaced and feel fairly confident that the bolt was reused. (Lord knows I would have been billed for them)

The good news was that for $11 and a little of my time, I got the sway bar hooked back up tonight and tightened the bolt with my torque wrench. I checked the drivers side bolts and everything was tight. I'll probably due the same job on the driver side in a couple of weeks. I'm sure glad that the Akron MB Dealership had the parts in stock. Hip Hip Hooray! .... and thank you for the advice.

P.S. Larry, I'll drop you a line if I ever decide to lay my 5spd to rest. I know the clutch is the same in the 240D and my 300D I just admire its simplicity and the fact that a intermediate DIY'er like me can troubleshoot her. I think I am also attached because my father purchased her almost new in Germany in 1985 (to avoid paying German sales tax) and had her Americanized in PA. It was his daily driver for years and I remember taking the car to my high school prom. I lost my father to pancreatic cancer three years ago and I like to run it as tribute...not to mentioned the ride in a Benz (my other vehicle is a Jeep Wrangler -absolute torture on the highway). I don't know of another brand of car that would be in such good shape at 271k.

Just one last thing.... the tech who worked on my car said I had the "dream" 300D. Here's why according to him:

1) It doesn't have climate control - just heater knobs (A/C was retrofitted by MB dealership in Germany before transport - don't recommend it - never worked right, never will)

2) It has manual windows

3) I don't have cruise control

4) It doesn't have a turbo charger

5) It has cloth seats

6) It has a manual transmission.

I guess I am lucky to not have to troubleshoot some of the more problematic accessories.

Thanks,


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