My 730i is experiencing trailing vibrations when going very slow- H E L P

[jarence]

Hello all My 730i is lately having very slight vibrations. Happens only under 50 kph. I brought it to my mechanic who usually fixed up my family's other cars (not bmws) and after 25 mins of testing, he believes it is the shafts. Prop shaft (engine trans to the rear axle) and the rear wheel shaft itself.He checked the underparts and said dirty flood waters, large potholes or big school bumps could have contributed to it. Somemore he told me to change to non ultra low profile tyres. I did lend my car to a young secretary as I came in late and blocked the pathway. She said she took it to Bandar Baru to collect her brother at the Acmar private school and then later drop him home and return to work immediately. It is 8 days now and the slight vibration is still there. Does anyone have the vibration problem like me? How much does the shafts cost? The problem occurs only at low speeds.

 

[Vincent Hor]

Check your 1. Giubo http://en.wikipedia.org/wiki/Guibo 2. Prop shaft bearing and 3. Rear diff support bushing.

 

[jarence]

I been to a few specialists. I find it strange because 2 of them said it is the rim, front shaft and steering mounts. The other specialist thinks it is the back axle diff but he can't guarantee it 100%.
In the end I took it to my long time mechanic who have a chain of other workshops in this region. I just hope I am not paying for things which is not needed thats all.

 

[Vincent Hor]

If it's the rims, the problem will be evident between 80-110kmh. Anyway no harm going to the tyre shop to check for roundness of rim, wheel balancing or even on-wheel balancing.

Where is the vibration? Front wheels area, under the driver seat or the rear wheel area?

 

[jarence]

Vincent

Those vibrations can be felt through the steering and seats.
The later became pronounced when I sat in the passenger seat beside the mechanic boss who was test driving. He took the bmw rims for checking and on-car balanced the rear tyres as well.

There were light scrap marks below the carriage but not bad or dented.
I told him that the vibrations happen when I drove the car home which was on the same day as I allowed the secretary to pick up her own younger sibling and drop him safely at their home. She return soon after.

When I drove back I thought I had a slow puncture or bulge. But I found nothing. The next day I thought the whole thing might have gone away but it was there. Once I go over 40 or 50kph, no vibrations.

This morning, I ask the secretary again and she said she drove like normal over bumps like she normally would with her own Ford Escape. She gave me the look like she wished she never drove my car.

Are shafts normally expensive?

 

[Vincent Hor]

Your car is relatively new. Therefore I would discount the problem with the draft shaft or the prop shaft. I am more inclined to guess that the giubo Or prop shaft bearings being the problem. Try checking this area.

 

[jarence]

Damaged or worn out prop shaft bearings would make a noise when moving? The mechanic want to change the whole assembly which include the guibo and prop shaft complete. Is this normal practice for my car?

 

[Vincent Hor]

When I mentioned the prop shaft bearing, literally it's not the bearing that is bad. It's the surround rubber holding the bearing that may have given way. So you don't hear any noise.

My advise is that you should try to get another mechanic's opinion. My mechanic is Albert Fang WP Auto 012-2017792 He should be able to give you a free honest opinion. After that you can decided who to carry out the repairs.

Damaged or worn out prop shaft bearings would make a noise when moving? The mechanic want to change the whole assembly which include the guibo and prop shaft complete. Is this normal practice for my car?

 

[jarence]

Thanks Vincent. :shakehands:

 

[jagmalhi]

hi! my e38 728 yr 2001 has the same issue..left passenger tire has trailing vibrations when i'm traveling at a speed