Expert: Tony Fox - 3/21/2011

Question
QUESTION: Vibration in seats at 50-70 mph

ANSWER: Without a lot of information from yourself I would have to suggest balancing the rear wheels first.
Looking at the front propshaft joint would be 2nd on my list.

---------- FOLLOW-UP ----------

QUESTION: Thanks for answering my question on BMW 540.I msport with vibration in seats . I have had all wheels balanced still there . No vibration steering wheel . Rear rotors have been replaced as well .  Thankyou steve.

Answer
Stick the car in the air and have a good look at the front propshaft coupling, mainly the 6 bolts to see if they have "moved" in their holes. (twisted) Very common and overlooked.Failing that disconnect the rear propshaft cv joint and test it for binding.

Good luck

Tony