Tracking a vibration
Thread Starter
Racer
Joined: Sep 2017
Posts: 452
Likes: 55
From: Marianna Fl
Tracking a vibration
I have recently noticed a new vibration that is speed dependent in my 1990 M6 coupe. I feel it start to come on at about 75mph. The weird part is I feel it through the seat, steering wheel stays strait without a vibration same with the gear shift. I only feel it like its under the driver seat. Tires where replaced about 18 months (8,000 mi) ago and this just came on a few days ago. The tires look fine, nothing to indicate possible damage. Any one have a similar experience?
Zen Vet Master Level VII
Joined: Mar 2016
Posts: 5,218
Likes: 1,174
From: Southlake, TX
You don't mention mileage, but I bet your u-Joints are original? You may want to inspect them.
BTW... although the tires are relatively new, they could have easily thrown a weight in 8,000 miles. A rear tire out of balance will not (generally) vibrate through the steering wheel but you will feel it in the back--A balance will not hurt.
BTW... although the tires are relatively new, they could have easily thrown a weight in 8,000 miles. A rear tire out of balance will not (generally) vibrate through the steering wheel but you will feel it in the back--A balance will not hurt.
Thread Starter
Racer
Joined: Sep 2017
Posts: 452
Likes: 55
From: Marianna Fl
You don't mention mileage, but I bet your u-Joints are original? You may want to inspect them.
BTW... although the tires are relatively new, they could have easily thrown a weight in 8,000 miles. A rear tire out of balance will not (generally) vibrate through the steering wheel but you will feel it in the back--A balance will not hurt.
BTW... although the tires are relatively new, they could have easily thrown a weight in 8,000 miles. A rear tire out of balance will not (generally) vibrate through the steering wheel but you will feel it in the back--A balance will not hurt.
Race Director
Joined: Apr 2003
Posts: 17,699
Likes: 1,667
From: moraga ca
Shift into neutral at that speed to try to isolate the vibration. If it still vibrates, it is from the transmission output shaft backwards or the wheels/tires. If it stops, it is engine, clutch, transmission related.
Thread Starter
Racer
Joined: Sep 2017
Posts: 452
Likes: 55
From: Marianna Fl
That was one of my first test and the vibration is not clutch forward.
Almost Retired
Joined: Sep 2004
Posts: 1,298
Likes: 236
From: Akron, Ohio
With drum brakes make sure the drums have the weights on them. Back in the day some mag wheels would hit the weight on the drum, so you knocked them off and had the tire balanced on the car. Had this problem with a 62 many years ago. If you can find a shop that still has one of those tire machines you can save the cost of new drums, but you won't be able to rotate tire without having to rebalance.
