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ber55ber55
03-11-2009, 09:13 AM
My main question is: How do you know if a drive shaft is bad? What actually goes bad on it? Can it be rebuilt? Cost?

I have replaced the centering bearing twice in about 6 months. Yes, I did correctly pre load it. I measured it out and everything. The guobo has been replaced in the last 6 months as well.

I am experiencing a pretty crazy vibration throughout the vehicle, in gear or out of gear. Ive checked to see if everything is tight (it was), but I didnt check the centering bearing again. Could a bad driveshaft be ruining the centering bearing over and over again?

I dont think its the tranny (5 speed), because the vibration (sound as well - w0w0w0w0w0w) does not go away regardless of if Im rolling in neutral, going 80+ on the freeway or driving streets.

As im accelerating it almost feels like a wheel shimmy sometimes (happens in third gear around 3-4 rpms). Any ideas or suggestions would be greatly appreciated
dennyg
03-11-2009, 12:02 PM
I had to replace a drive shaft with rebuilt one because U joint was no good and they are pressed on. Rebuilt shaft was 175.00 and had center bearing on it. Not sure if that is your problem but its possible.
ber55ber55
03-11-2009, 01:42 PM
How can you tell though, from a visual inspection that the driveshaft is bad?

Do you feel it in the driving when the driveshaft has a problem?

How is it diagnosed?

What does it look like when the U joint is bad?

Thanx
h2oyo
03-11-2009, 06:26 PM
How can you tell though, from a visual inspection that the driveshaft is bad?

Do you feel it in the driving when the driveshaft has a problem?

How is it diagnosed?

What does it look like when the U joint is bad?

Thanx

If the U joints are worn or bad you will see and or feel movement in them by hand. If there really bad you will see the U joint move inside the end caps. Its not hard to tell if they are worn. No side to side play up and down nothing.
Kibokojoe
03-11-2009, 08:34 PM
I just replaced the driveshaft on my sons 7. Once the center bearing is loose you can tell very easily if any of the bearing are toast. I the case of the 91 735i we had to replace the entire driveshaft because there are no replacement bearings available. Shaft came with center bearing...$400.00 USD
Kalevera
03-13-2009, 07:15 PM
The U joints get "notchy" and if totally neglected will seize up. The CV, on those so equipped, can lose its grease and die as well.

The center support failure could be because of an inferior replacement part, or because one of the joints is bad and putting undue stress on it....