What is the purpose of the self leveling suspension? What does it really do and why does Mercedes use it in some models but not others?

Besides E class wagons (123, 124, 210, and 211), Mercedes has used it in some versions of the W201, W124, W126, W140, R107, and R129. I get the concept of compensating for a heavy load in a wagon or even a big sedan, but what was the idea of using it in the W201, W124, R107, and R129? Besides compensating for a heavy load, what else does it do? If it has such great benefits in some models, why not use it in all models?

Just curious. Thanks.

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Michael

1988 300 SL (5 Speed)
1994 E320 Wagon
1997 C230

Well, it keeps the car level all the time.

The W108/109 chassis had a mechanical system that is usually long gone by now -- and replaced by a simple spring. The W109 had air suspension, too, not steel springs.

The hydraulic rear suspension also rides MUCH nicer than springs and shocks, but is also mor expensive. Usually optional on most models, although not in the US. European taxis almost always have it, keeps the rear from squatting so badly when really loaded up.

The W116/W126 6.9 and other various luxury models had full hydraultic, and many top line sedans have rear SLS (and it's optional on all).

I really like the SLS in the TE, and I think it handles BETTER than the steel spring suspension in the 300D.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

As stated above, basically the SLS helps the rear of the car to be levelled in case is heavily loaded.

But that's really about it. I have owned three T's (one 123 and two 124s) and have driven several sedans of the same line. Almost never in any situation I could tell the difference in ride or handling with and without SLS.

The only time you can feel a difference, is when the SLS system fails and then your rear axle becomes a cement grave and the slighest hole will make it bounce up to the sky. Then, be prepared to mortage your house to pay for repairs. That is about the only difference with this set up and the regular springs.

I admit it, when the Ts were heavily loaded, the ride was smooth and competent. Although, this happened about twice a year. So, were is the advantage???

Thankfully, my S 500 L is Euro spec and does NOT have the SLS.

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A. Rosich
CL 500, 1998
S 500 L, 1998
E 320 T, 1995 [Sadly sold ]

I think it also helps keep our 190-D 16 valves level when screeming around corners!

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Current:
2014 VW Tiguan SEL 4Motion 43,000 miles.

2016 Hyundai Santa Fe Sport (wife's).

Past:
2006 Jetta TDI 135,970 miles. Sold Nov. '13.
1995 E-320 Special Edition. 220,200 miles. Sold Sept. '07.
1987 190-E 16 valve. 153,000 miles. Sold Feb. '06.
1980 300-D 225,000 miles. Donated to the National Kidney Foundation.
1980 240-D manual, 297,500 miles. Totaled by inattentive driver.

Thanks. I get that but still feel like I must be missing something. What you all are saying is, for a heavy load, it's nice to have but some sort of engineering overkill? What does this thing really do? There must by more to it. Why would the Cosworth W201 or 500E have it? I really feel like I'm missing something... What about day to day? How fast does it react to changing loads and is it a kind of active suspension? Say I was driving the wagon without a load at 125 mph and was turning, would the SLS compensate in real time according to the load for each side? Is it slower than that? Does it always do both sides equally? On another note, is the real purpose of this thing to sacrifice itself for more expensive rear suspension parts of vehicles that are expected to receive heavy hauling or racing service? Correct me if I’m wrong, but to refresh the system (which will be needed once about every 100,000 miles), is relatively cheap, about $200 for parts (accumulators), $50 for fluid, and a couple of hours of labor. If it prolongs the life of other, expensive rear suspension bits, would it not save cost over time? When I drive the wagon, I feel like SLS has some intangible value that I can’t quite put my finger on. Day to day, what does it really do for me?

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Michael

1988 300 SL (5 Speed)
1994 E320 Wagon
1997 C230

The best thing is that you can switch from soft to hard ride...with a push of a button
And you can manualy adjust the suspension hight!
There is no comparison!
Refering to 129

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DRIVE IT LIKE YOU STOLE IT!

To give you a more serious answer, I'd have to be honest and tell you that I've never really felt the suspension compensate for anything. For that matter, there's a loud banging sound in the left-rear side of the car whenever the suspension comes back out after compressing over a bump. Very loud, irritating, and it hasn't been figured out by my mechanic who happens to specialize in these cars. Go figure.

That may be one reason why so many 16 valve owners replace the rear self-leveling suspension with more conventional ones after they begin to have problems.

__________________

Current:
2014 VW Tiguan SEL 4Motion 43,000 miles.

2016 Hyundai Santa Fe Sport (wife's).

Past:
2006 Jetta TDI 135,970 miles. Sold Nov. '13.
1995 E-320 Special Edition. 220,200 miles. Sold Sept. '07.
1987 190-E 16 valve. 153,000 miles. Sold Feb. '06.
1980 300-D 225,000 miles. Donated to the National Kidney Foundation.
1980 240-D manual, 297,500 miles. Totaled by inattentive driver.

"loud banging sound in the left-rear side of the car "

You better think of taking your car to another 'mechanic'
When diaphragm sphere burst loses the nitrogen and there is no 'back up' pressure to support the load on the shock!
There is banging just because there is no pressure...simple as that

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DRIVE IT LIKE YOU STOLE IT!

The system you are referring to is COMPLETELY DIFFERENT from the SLS fitted to the T series and some sedans as either standard (in some markets for high end models) or as an option (for almost ALL models in most markets).

The SLS just levels the rear axle, period. No buttoms to adjust ride characteristics or anything. No advantages over the regular setup in terms of handling and ride (unless, as said many times before, the car is fully loaded).

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A. Rosich
CL 500, 1998
S 500 L, 1998
E 320 T, 1995 [Sadly sold ]