need some driveline help..

[SinisterE30]

okay guys so i replaced the carrier bearing in my e30. I marked the driveshaft so i would make sure to put the two halfs back together correctly. but at one point or another they got rubbed off or something IDK. they are just not there anymore. I have been doing some reasearch and there are supposed to be some white dots fromt he factory balance. i can find one white mark on thre rear half of the shaft but not the front half that holds the carrier. so i did some more reading. found out that if i put the u joint in "phase" then i can get close. well to the best of my knowledge that means that the u-joints should be kinda like ]===[ if that makes any sense. well i pulled the drive line back out and tried that. now its worse. I need some help. what does in phase mean exactly and where might the second set of "white dots" be located... Im trying to avoid having to take it down to a shop to get it balanced cause im kinda broke at the moment from buying the car. and i dont get payed for over a week from now. this is supposed to be my DD. any pics of in phase or the location of these white dots would be of great help. thanks!!

[jw 325ic]

If it didnt work one way when aligning the ujoints, flip it 180 and try again!

[SinisterE30]

Well i am going to try that tomorrow before work. Im just trying to figurr out if my understanding of "in phase" is correct

[jw 325ic]

Just make sure the ujoints are lined up.

Look at this for example:

[SinisterE30]

Thanks a bunch! Thats how i have it. I will flip it 180 tomorrow nd see if that helps

[jlevie]

I'm going to have to guess that you are getting vibration from the drive shaft. What the probable cause is depends on when the vibration occurs. On the assumption that the u-joints are properly phased, if it happens at low road speeds and is worse with harder acceleration the cause will be binding joints in the drive shaft. Vibrations from a drive shaft out of balance won't show up until the drive shaft is spinning rather rapidly which will only happen at very high road speeds Probably not until you see triple digits on the speedometer.

[SinisterE30]

It was a matter of the driveline being out of balance. But it was a vibration at like 40+ mph. I cant imagine trying to hit the triple digits with a out of balance DS. But it all was on account i had the u-joints phased 180 off.

[jw 325ic]

So you switched it and now its good?

[SinisterE30]

yeah its great now. Just like it was before. thank you for the help :)

[jlevie]

Not that I'm trying to rain on your parade, but 40mph with as high as a 4.10 differential would mean a drive shaft speed of only 2300rpm. That typically isn't enough rotational speed to cause balance issues to show up. However, a used drive shaft will have worn in and there can be a big difference in how much the u-joints bind if you assemble the shaft with the u-joints 180 out of where they have been.