I purchased a certified pre-owned 1994 740IL 18 months ago and have been trying to correct a vibration which occurs usually at 55 mph on up. (it is at it's worst at 63mph.)
I have recently been told by one of the senior technicians at my dealership that the pre 95 7 series and pre 96 5 series have a design "characteristic" (ie. flaw) which allows for a harmonic vibration to occur at the above mentioned speeds. I find it hard to believe that BMW would have allowed such an oversight to occur.....and if it did, not provide a fix for it.
It should be noted that this car has never been damaged and I don't abuse it. In the time frame in which I have owned the car, it has been taken to the dealership numerous to try and correct the vibration. Here is a not so brief history on what has been done, (in chronological order,) to try to correct, or at least affect, the problem:
-Balance tires and alignment.
-Replaced upper control arm bushings due to wear.
-Replaced all 4 tires.
-Rebalanced tires again.
-6 months later, noted excessive outer tread front tire wear, found alignment way off, replaced front tires and performed alignment.
-Recenter steering wheel.
-Replaced front brake rotors and pads due to normal wear.
-Checked wheel rims, one found very slightly bent, had it repaired.
-Replaced, again, upper control arm bushings (the right one was leaking.)
-Right front wheel bearing wore out, replaced both from wheel bearings.
-Idler arm checked, no problem found.
-Some exhaust hooks found missing, replaced.
-Replaced all 4 tires again due to unrelated sidewall puncture damage.
-Performed wheel balance and alignment.
-Rotated and re-balanced tires again.
All the above mentioned items have had little if any effect on the vibration and none have ever eliminated it, not even temporarily. Most of the items were paid for by the BMW cert. pre-owned program and the dealer's good will.
I don't even want to begin talking about the other things which have gone wrong with this car aside from the vibration problem......lets just say I got my money's worth from the CPO.
My old 95 318i 5sp. which I traded in was much better behaved....and much more manueverable! I guess the 7 series is not nearly as reliable.
Thank you for reading through all this....any thoughts as to how to correct the vibration? I am tempted to dump this car!