88 560 sel
 

I have a 1988 560 SEL that has a bad shimmy at about 45-55mph... can anyone help with this issue.. what are the common things that cause this?

Tire balance--did you lose a weight?
Belt separated--did a steel belt in one of the tires go cattywampus? (my Dad always used that word--don't know if it's real!!)
Air pressure--is one or more tires low (for as big as it was my 560 SEL was very sensitive to air pressure)
Rotation--sometimes failure to rotate tires will cause sipe wear that suddenly manifests as if it were the Mother of All Earthquakes. (especially true with the 31's on my old Wrangler, scary!!)

Suspension--tie rod ends, ball joints, etc, etc.

Did the problem arise suddenly or has it been building? Check the easy first, air pressure. then balance. Good tire guy can sometimes spot a separated belt from the next county. (good tire guys are normally found at good tire shops, not usually in the automotive department of department stores--just my observation)

Good luck!!

Flex discs and/or driveshaft center support too.

Bent rim? If you can "feel" what corner the wobble is originating from...try moving the rim around and seeing if the wobble follows. I have spent many hours and $$ chasing suspension wobbles only to have it come back to a bent wheel.

Steering link damper: it must provide some damping, or you see the result.
Or a bad tire: try moving the tires around and note any changes.

i've had "shimmy" on 86 560SEL at around 65-70 for few years, even after replacing all worn front end parts, and numerous rebalancing.

been on a 2000 mile trip and it just drove me nuts... so pretty much identified the problem as the right front tire. replaced it with the spare and shimmy is gone.

next step is to replace all the tires... they're more than 5 years old, a "good" tire guy told me after he rebalanced them that he "really" believes the tires are too old and just need replaced. said they weren't really out of balance. 1/2 an ounce at most. he drove the car and was sure it was the tires.

guess he was right. :)

Lower ball joints, brake support bearings, tie rod ends, and check wheels first make sure there not bent , rotate to see if problem goes away, shimmy under braking= rotors warped.