Vibration 55 to 65km - Dealer less than helpful and expensive

[browned]

Hoping to get some more ideas on a vibration occuring during cruise speeds, minor load, from 55 to 65km. I cannot notice any vibrations in the steering wheel, it is more the center of the car close to drivers leg.  Local ford dealer has replaced the drive shaft hanger bearing and balanced it ($1+K later) still exactly the same, oh and they are insisting it needed to be done to pass the warrant of fitness, although the WOF form clearly states it failed due to right rear tire. So they are now saying it is normal and all old Falcons do it. But they will replace both half shafts for $5K in parts and then labour on top. No thanks.

 

I am taking it to another shop later this week. Hoping they will diagnose it better having wasted $1k already.

 

- Vibration 55-65km, cruising at 55km, no real load apart from staying at 55km.

- No vibration at idle, stationary, and I cannot feel it above 65km.

- Front wheel bearings replaced 40K ago. Not sure the rear ones have been replaced. Just passed WOF, assume they would have check them.

- Not sure on engine mounts, but could be an option, although I would think it would vibrate all the time.

- any other ideas?

 

Thanks

[arronm]

Have you had the rear wheels bbalanced. 

 

Rear gearbox mount 

[browned]

Had the rear tyres changed due to wof failure so they were balanced in the shop. Will get the mount inspected.

 

Starting to think the vibration is there at any speed above 55km, just cannot feel it as well as between 55-65km.

 

Thanks

[StephenW]

My Mk II is doing a similar thing but only when it's cold. While it was under warranty, the dealer tried to work with me once I was able to demonstrate the problem. The last thing they did, after all the standard stuff, was to swap the tailshaft out of a Falcon off the lot. The problem seemed fixed, though the fault did not transfer to the other Falcon. All went well for a month or so then the vibration slowly resurfaced. My car was out of warranty by now, so the dealer lost interest as they weren't going to get any more money from Ford. My local independent Ford expert had a go as well with no joy. He said the next step was to pull the transmission; a big job for a maybe.  I've learned to live with it since it goes away after about 10 minutes of driving.

 

As far as the OP goes, I'd try getting the car to vibrate and then put it into neutral and coast. If the vibration goes away, that will eliminate the wheels and tyres.