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  #1  
Old 07-21-2003, 11:23 AM
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Join Date: May 2003
Location: Iowa City,Ia
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420SEL unstable in cross winds

This my first post to this forum and my problem is, my 1990 420sel seems to oversteer in gusting cross winds. All suspension components have been replaced and it has been aligned twice by the MB dealer. They say that this is inherent in the 126's, is this true? I have searched but don't find any info on this subject.

MB says that all four wheels are in spec. and there is nothing else that I can due. Please help
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  #2  
Old 07-21-2003, 12:22 PM
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Location: Colorado Springs, CO
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You shouldn't feel the wind. If all suspension parts are good, then insufficient toe-in (alignment) is a likely cause. Too much toe-in creates understeer and possibly outside tire wear. Too little creater oversteer, wind sensitivity, and possibly inner tire wear. Just because the tires wear perfectly doesn't mean the alignment is "correct". BT, DT.


HTH,
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  #3  
Old 07-21-2003, 02:47 PM
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I'll second Brian's reply. Even wear on tires does not necessarily indicate that everything is 'a-okay'. There could also be structural problems within the tires, especially the sidewall that may not show up, visually, for awhile.

This behavior is definately not normal for a W126 - my 560SEL is one of the most stable cars I've driven.

jlc
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'87 560SEL 267K (177K on motor) Blue/Blue
'98 Buick LeSebre 60K (wife's car)
'56 Imperial Sedan 124K
Past Cars:
'67 Dodge Monaco 130K (Sold)
'87 Chrysler 5th Ave 245K and going strong (sold)
'73 Plymouth Satillite 175K (sold)
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  #4  
Old 07-21-2003, 06:13 PM
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Have you checked the play in the steering gearbox. Excessive amount of play (transmitted through to the steering wheel) will cause a wandering effect.
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  #5  
Old 07-21-2003, 06:53 PM
bmunse
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I agree with the advice to look at your tires. After checking twice the toe in is probably right. Bad tires can make a car dangerous to drive. What is funny is that they say that the 126 inherently has this problem. Thats rediculous! My 420 sel is rock solid throughout its speed range in any wind.
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  #6  
Old 07-21-2003, 08:00 PM
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i have owned a 560sel and a 560sec from new in 12/86. both cars have been immaculately shoed and maintained for all of their mileage. the sel is a couple thousand miles from 250,000. the sec is just turning over 81,000.

both cars have always been susceptible to cross wind interference[i can't think of another word]. when i first noted it shortly after taking delivery, the service director of the dealer told me that it was systemic to the series.

when questioned, so did the zone rep for mbusa.

and most interestingly, so did some of the reviews of the series in the buff press.

i have found a susceptibilty to cross winds to be an idiosyncrasy of the series.

other posts notwithstanding.

i also own a 1979 6.9, a 1995 e320cab, and a 1997 s500c: none of these vehicles are as cross wind sensitive.
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  #7  
Old 07-21-2003, 11:12 PM
bmunse
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Hi Albert, Your Sel has rear leveling suspension I presume. Does your SEC have that also? Did they say that this was just on 560's or on all 126's? As I said earlier, my 86 420sel is very steady.
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  #8  
Old 07-22-2003, 01:56 AM
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yes, of course, the 560's have the hydraulic compensated rear suspension. i think it was standard equipment.

did m-b not put that on the 420's?

if not, do you think the absence would make the 560's more squirrely in cross winds? of so, why do you think or know?

i mean, it not as susceptible as my 1996 suburban, but cross winds are noticeab le as a matter of directing the car. and sudden gusts over 25mph require attentiveness.
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  #9  
Old 07-22-2003, 09:32 AM
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Question

Thanks to all for your interest. I would like to add That I have had the tires balanced on the Hunter 9700 by the Hunter Rep. ( a long story that I won't go into here). All four tires checked out perfectly. I usually run 32lb front and 34 rear pressure. This car has standard suspension and compared to the my 1980 280se it is much more difficult to drive in cross winds
It has been suggested in other posts that I check steering adjustment since if it was adjusted to tight it would cause the same symptoms. Since I can tell that the steering box has been R and R'd prior to me purchasing the car and there is some play in the box I am suspecting that this could be the problem. I can make an adjustment from below but it would be by feel. I plan to make a small adjustment and wait for a windy day.
Since I have been considering replacement of the steering box anyway I would ask for recommendations from the group on experience with rebuilt box's and the best suppliers. Price's on E-bay range from $265 to $400 for rebuilt's. Also, I have never done this job, is there a pictoral anywhere and/or any suggestions on the procedure. Also, are there any other parts that should be repalaced along with the box.
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  #10  
Old 07-22-2003, 09:41 AM
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Carl,

I have never been to Iowa City. However, my '87 300D has been across South Dakota, Nebraska, Montana, Wyoming, Utah, Idaho, and other states where it can be VERY windy. On a trip last summer my '87 300D (W124 chassis) was VERY difficult to keep in lane. When I returned home to Tennessee I spend the next few months trying to find out why. I went to the DEALER for an alignment and they fixed front toe-in.

I have heard that W124's and W126's are sensitive to winds. This is generally from people who have the problem and "live with it". However, others have had NO problems and they say they are not sidewind sensitive.

I have also changed the steering box beacuse mine was previously adjusted TOO TIGHT. IF its loose, then it CAN be tightened with good results. Just make sure to leave 10-25 mm of play. Without play the box will be damaged.

I've replaced the gearbox on my '87 300D after it was diagnosed too tight. On the straight six diesel, it was easy, nothing in the way. Just needed a Pitman arm puller & snap ring pliers to get the circlip on/off that goes over the Pitman arm. No alignment is needed. On the straight six diesel, there was no exhaust, etc to get in my way.

HTH,
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  #11  
Old 07-22-2003, 10:56 AM
bmunse
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Quote:
All four tires checked out perfectly. I usually run 32lb front and 34 rear pressure.
Carl, Try reducing the rear air pressure to 28 or 30. By doing so you will allow the tire sidewall to absorbe some of the sway. At 34 lbs your side walls are stiff and transferring all sway that they could be absorbing. I keep 30lbs in all tires. It works for me.
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  #12  
Old 07-22-2003, 11:56 AM
bmunse
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Quote:
yes, of course, the 560's have the hydraulic compensated rear suspension. I think it was standard equipment.
Yes Albert, I think the 560 was the only one of the 126's to be treated to the rear leveling, and I wasn't sure about the coupe. I test drove a 560 when I purchased my 420 and felt a boat like float to the rear of the car at highway speeds. I can see how that would give the 560 a greater chance for a negative experience when pushed from the side by a gust.
I find it hard to understand how the Mercedes service organization could try to explain away a drivability problem as common as cross wind gusts.
Given all this, my 120,000 mile 1986 420 SEL drives well at speed (75 to 85 mph) with gusting and therefore would suggest that my car is fine and any 420 that sways is not fine. Good tires, alignment, steering linkage, steering gear box and a service department interested in helping you make your car satisfactory should all be present. Barry
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  #13  
Old 07-22-2003, 01:29 PM
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Just drove my 87 420 from Phx. to DC about a month ago and could definitely feel crosswinds. The car was never difficult to keep in the lane but I had to pay attention (brand new Pirelli P6000s, btw). I will try the recommendations re steering box, etc. here but we need to remember, this is a BIG car that creates a lot of wind resistance from the side so I expect that some play is inevitable.

John

87 420SEL
00 C230K
00 A4 2.8Q
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  #14  
Old 07-22-2003, 06:58 PM
Q Q is offline
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I think people's interepretation of cross-wind can be widely different. I lived in GA and never really had a problem with my 126 being squirrely in the wind. Since living in the Dallas, Texas suburbs, I know what cross-wind is. The average wind speed here is a shade higher than "the windy city". 25 MPH gusts really drive me crazy here trying to get the car to stay centered. I have replaced ball joints, sub-frame mounts, tie-rod ends, steering shock, brake-force guide rod bushings, idler arm bushing......with no change at all (was not replacing trying to solve the problem, they were all worn).

I wonder if adding a bit more toe-in than spec would help the problem.
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  #15  
Old 07-22-2003, 09:42 PM
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Location: Omaha, NE
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Carl,
If your car has > 100 k miles and the subframe bushings haven't been replaced, I'd consider doing that. The W124 and W126 chassis do wear these out and they can cause a good deal of instability at cruise.

I have NO problem believing a dealer would not be interested in correctly diagnosing a drivability problem in a W126.

If you're willing to drive a bit for a really accurate diagnosis, I know a GREAT mechanic in Omaha.
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