how to tell if your U-joints are bad?

[E30MACK]

So I just replaced my CSB and my gubio and the PO recently replaced the trans and engine mounts and there is not the viration at around 35 that I was having but now around 50mph it vibrates pretty bad and the entire car has a light vibration(enough to shake my seat constantly) from what I have read, considering what I've already replace I'm guessing U-joints. but are there other ways to confirm?

[jlevie]

Pull the drive shaft and check the condition of the u-joints. If they are loose or stiff the drive shaft needs to be replaced. But, you may be able to decide w/o removing the drive shaft. If the rubber mount of the CSB was torn, the drive shaft needs to be replaced.

[nando]

yeah you have to pull the shaft (heh) and inspect them by hand. they might also be really tight/notchy. They should be smooth but solid. they normally last a long time, nearly the life of the vehicle, but can wear faster if other parts are not kept up (CSB, flex disc, etc).

[jlevie]

they normally last a long time, nearly the life of the vehicle, but can wear faster if other parts are not kept up (CSB, flex disc, etc).

Not in my experience. In the general case a BMW drive shaft will need to be replaced around 150k miles. The rear u-joints are ususally the first to go and the main cause of failure will the affect of heat on the lube in the u-joints. In almost all cases, failure of the rubber mount of the CSB is the clue that the drive shaft needs to be replaced.

[E30MACK]

huh, well the gubio was in good shape no tears or even any wear, looked brand new. the CSB however was a good thing to replace but even still it wasnt horrible. it seemed like the drive shaft was a little sloppier at the back toward the differential....any ideas?

[jlevie]

If there was any slop in the rear u-joints the drive shaft is bad.

Did you match up the paint marks on the drive shaft when reinstalling it?

[E30MACK]

I did indeed match up the white paint marks....so what am I looking at price wise for a drive shaft? also, does the part from the CSB back to the differential need replacing as well?

[E30MACK]

so I guess Im looking at a remanned drive shaft....cheapest one I found is $342.86 plus a $60 core charge......general concensus?

[jlevie]

I'd expect to pay about $450 for a quality rebuild form DriveLine Services of Portland. Those are the only folks I'd trust to do the job correctly.

[E30MACK]

ouch...so I guess maybe drive it till some one crashes there car with a newly rebuilt driveshaft in it and hope to get it for less or what?

[E30MACK]

what are my options in reference to a newer(E36) driveshaft?