when I am travelling at a slow speed such as 40km/hr the car wiggles back and forth (left to right) from the frontal portion of the car. I have noticed this happening in old cars and call it the "old car disease". Its something with the suspension, what could it be?

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99 C43
98 S420
99 C230K
01 C240

Nobody answered you but I am pretty sure it's just bad tie-rod ends. An easy and inexpensive fix. Jack up car, remove the frt wheels, grab the hub and try to wiggle back and forth at the bottom and top. Any play is too much. Replace worn parts and car'll be good as new.

maybe the tires? yeah but I am pretty sure its the tie-rods. It is barely noticable but I think it will get worse.

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99 C43
98 S420
99 C230K
01 C240

Tires out of balance? What speeds? 40-60 is usally tires. Also control arm bushings and worn front end componets.

I agree, tie-rods would be my first guess.

On the other hand, pretty much everything you could see spread out in front of the car can somehow cause a lousy stearing.

But start with the tie-rods, they are the cheapest to replace.

BTW: My girlfriend asked her local Mercedes shop in Austria how much the wheel alignment on her W 116 would cost.

They replied: "Oh, these old cars! That would be, without seeing the car, about $ 200. Probably the tie-rods are shot at those car, this will end up at around $ 500".

Well, she told him her opinion about ripping people after we got the wheels aligned for $ 50 and after we replaced one tie-rod for $ 30.

It is such a disgrace how some of the workshops try to treat people.

Kind regards
Eberhard

If the car is hobbling from side to side it could be a broken steel belt in one of the tires.Very easy to check.Rub you're hands flatly on the tire tread.It should feel even across the surface, if it feels wavy you have found ur problem

And while feeling the tire if you can detect "cupping" say along an edge, this is indicative of an out of balance tire and possibly a loose/worn wheel bearing.