Steering wheel shimmy - HELP!

[inetd]

My 98 S500 steering wheel shakes in the 40-55mph speed range only during normal driving. Below or above that speed it disappears. Hard braking in that speed range amplifies the shake quite a bit. But as soon as the car slows down, it goes away. Wheels are chrome 16" Mercedes, and show some signs of wear, but they look round to me and the tire dealer agrees.

On brand new Mich MX4s, I took them back and had them rotated and re-balanced, but steering wheel shimmy did not go away for that speed range.

I took it back to the tire shop once again, this time they "load balanced" all 4 wheels/tires. Apparently the 2 back tires were poorly mis-matched to the wheels, where the tire needed to be rotated on the wheel about 90deg or so.

A re-check after adjustment gave a much better balance figure. I'm afraid it did not fully go away however.

I replaced the steering damper (steering shock absorber), and am out of ideas. Problem persists.

Someone mentioned this may be driveshaft bushing related?

Perhaps other steering bushings? Ball joints? My experience with steering bushings is when they act up, it happens through the entire speed range?

Any help here would be MOST appreciated! I'm gonna tear my hair out (actually it's already out, but I didn't tear it - it fell out)

 

[mercedes lover]

Sorry mate cant help you, but I know how you feel just got rid of a car because when I was braking the car shuddered like I was in an earth quake. Swapped the car in because needed new disks & brakes but stupid garage said they may of had to put new bearings as well. Hope you sort it out, 1 question how nice is your S class to drive?

 

[Ian B Walker]

Before this post gets moved to the wheels and tyre section I would plump for track rod bushes being worn. Usuall disclaimer, I may be wrong

 

[Shude]

Before this post gets moved to the wheels and tyre section

Moving...

 

[inetd]

my apologies - I wasn't sure if it was tires/wheels or not. I'm even thinking drive shaft or DS bearings.

Can someone help me with tie rod end/bushing diagnostics? What's the method to check if they are worn out? Are they hard to replace? I thought I read somewhere I need a compression tool of some sort for that.

Also - could this be ball joints? Again, how do I diagnose those? Can you lube ball joints?

Here's a pie in the sky idea - I wonder if this could be caused by bad rotors? Seems a friend told me one time that an out-of-round or misbalanced rotor could wreak similar havoc.

Thank you all so much for your responses!

 

[andy_k]

I'd go with Ian's suggestion but I wouldn't discount brake disks either.

You can check the rotors yourself really easily. Jack the car up and put it on an axle stand (all the usual safety disclaimers here about solid level ground, handbrakes and chocked wheels apply) then set up a marker such as a felt pen attached to something solid (another axle stand is perfect) so that it's tip just touches the brake disk, Spin the wheel slowly and see what happens to the line it draws around the disk. If it's broken or pushes the pen away then the disk is most probably warped and should be changed.

You can check the trackrods whilct the car is off the ground. Pulling at the sides of the wheel whilst a friend looks for any visible play. attacking them with a large lever to see if you can force any movement.

Check if there is any play in a wheel bearing by attemtping to rock the wheel whilst holding the top and bottom.

HTH

Andy

 

[sportyreptile]

S Class have idler bushes??

If the S Class is like the E Class (W124) check the steering idler bushes as well for play - big lever/screwdriver method as trackrod bushes.

Replaced my idler bushes and steering damper (prior to bush change) and the feel of the steering is much better.