Vibrating 126 at high speeds - What could it be?
 

The wheels have been balanced with new set of Michelins Primacy tyres and new rims. Suspension and struts have been changed. Yet, the car still has a slight vibration at 150 to 170 km/p.

What could it be?

:confused:

Driveshaft? Flex joints? Do you feel the vibration primarily through the steering wheel (front suspension probable cause) or through the drivers seat (other causes, including those mentioned above)?

Kerry, just to eliminate the possibility of a wheel/tire problem -- I'd rotate them and see of the problem persists. If so, move on to the driveshaft.

The tyrea are new and just balanced with perfect "0" all round. The vibration is noticeable as I have a toll reader stuck on the windscreen and it moves vibrantly. Other than that, I can't really notice anything else moving with much excitement.

What would be up with the drive shaft and how can I have this checked?

ymsin,

A while back, M-B had a lot of consumer complaints with the W140 chassis and tire/wheel vibration. The M-B dealer in Tiverton, Rhode Island was doing a service on my 190E 2.3-16 about ten years ago, and he talked me into using the tire balancer M-B prescribed for resolving the W140 series issues. It involves balancing the tire/wheel assembly while it is mounted on the car, and I was impressed enough with the way the tires just stayed stuck on the ground with no vibration that I went back to have it done again when the tires were replaced. If they were closer, I would do the tire service there all the time as there was clearly a difference (improvement).

I would expect a driveshaft balance problem to be accompanied by some noise, also related to the rotational speed of the driveshaft which is around three times as fast (three times the frequency) of the wheels. So your vibration sensation would be pretty high frequency at 150-170 kph.

Hope this helps, and good luck. Jim

Thanks Jim.

The balancing I had a few days ago was done in the manner you described.

As I was driving to work this morning, I remembered that this car has very sensitive balancing requirements - more so at high speed. I got it eradicated once, and now I suspect perhaps the balancing wasn't done on spot.

I might just leave it for the time being as it only irks me when I'm doing way above the legal limit, which I shouldn't be allowed this little simple luxury.

I should drive at 110 km/p and just watch the roads SLOWLY and QUIETLY rolling by without much fuss.

Thats the problem when driving a silent, but capably fast machine. More so when its done in absolute comfort.


:)


ps. I will still check on the shaft to be doubly sure.

I would have your mechanic check the rear drive shaft. I went through the same issue and as everything else was ruled out my mechanic said it must be the universal. Sure enough when he removed the rear drveshaft and we saw it together the universal is free in one direction and slightly binds in the other. (Note slightly). Another good item to check is the transmission mount. I have not cured the problem on my car. Learnt to live with it and be less sensitive.

I understand that another problem on a Benz especially on the 126s, is the mount for the brake control rod. This is the rod going from the lower a-arm back to a mount in the body. We used to call them compression rods on Datsuns. The mounts can develop some slop and will allow any slight imperfection in the tires or balance to show up big time. I need to replace them on my 560SEL. One of mine has a torn boot and actually clunks when turning lock-to-lock. Before I put new tires on, anything over 70MPH was scary;the car shook so bad. Just one more project....

Looks like I'd be kept busy going from one point to another.

Thank you all for your pointers. Just hope one is right.

:)