Drive-Shaft carrier bearing?

[Grendel415]

Hello, I am getting a thunderous noise midway up the console in my 1994 540i with 160000 miles on it. I put it on stands today and inspected the guibo but that looked fine as well as the rear end. The noise is coming from where the center or carrier bearing is. Is this a shot bearing or a drive shaft out of balance? This noise only happens at take off and disappears after it gets to about 20 mph. If I baby it, it doesn't happen at all. I want to know what to expect if I am the one to drop the exhaust and heat shield. Is it difficult to replace the cb? What should I be prepared to replace? Any help with this is greatly appreciated.
Thanks

[Bruno]

A bad bearing will give you some bad vibrations and noises at take off then gets quieter. Exactly what you are describing. So my guess is that your diagnostic is correct. Time to put the car on jack stands, remove the exhaust, heat shield order a new bearing and install it.
Once important think, break the driveshaft bolt (the one connecting both side of the driveshaft) before you remove anything.
Mark the driveshaft also before breaking it in two, both pieces are individually balanced but still, you want to put back the driveshaft the same way you found it. A hammer and chisel will take care of removing the old bearing, put the new one in the same direction. Then use a super large socket (if you have one) to drive the new bearing back in place.

Some part places will sell you the bearing only, make sure that you are getting the whole assembly.

Good luck, just did it this week on my car during my 5 speed swap.

[rockin1978TA]

Make sure your U joints are good before you waste any time with the center bearing. I had mine all apart and replaced the bearing, noticed the u joint in the front next to the transmission was tight. I put the car back together anyway seeing I had to work on monday. The new bearing lasted 2 weeks before I heard center bearing support banging on the tunnel. I pulled it again and found a good replacement from another car. I have gotten pretty quick at this job though, last time was under an hour.

[Bruno]

While we are talking about driveshaft, I changed the center bearing in mine then I realized that the driveshaft wouldn't match the diff so I picked up the front 1/2 of the 525i driveshaft and the rear 1/2 of the 535i driveshaft and didn't bother with the balancing.
And no vibrations so it would seem that each 1/2 are balanced separately like flywheel and pressure plates.

[leicesterboy15]

I just had mine replaced at a garage - I know what you're all thinking but I don't have the time these days :(

Mine would rattle on take off then quieten down. Turned out my gearbox mounts had gone (which you could only tell on full bore take off!!) and this had put the bearing out of line and worn it down quicker.

When I spoke to a guy at BMW he said the only perishable parts in there were nos 1, 4 and 7 (centre bearing and mount) in this diagram:

RealOEM.com * BMW E34 540i DRIVE SHAFT-CEN.BEARING-CONST.VEL.JOINT (http://www.realoem.com/bmw/showparts.do?model=HK42&mospid=47398&btnr=26_0094&hg=26&fg=10)

I got them and the gearbox mounts replaced and all is good in that department!

[Bruno]

You mean 1, 2 and 6 in the diagram :)

[leicesterboy15]

You mean 1, 2 and 6 in the diagram :)

Well....maybe! Ok you win.

Although I just got the whole thing (bracket and bearing) as I didn't want to have to open it up again.

[Grendel415]

Thank you for the confirmation and the heads up. My friends got a lift that will make this a cinch or at least I hope. Anyone got any idea whether you can reprogram a automatic tranny when it starts fouling up like hesitating and being a little jerky at take off? But acts great once it's moving!? What could this be signaling that is not right?

[Grendel415]

So I replaced the carrier bearing and mounts, but I'm still getting a slight vibration. The drive shaft was put back together right. What do you think? Guibo?

[Bruno]

Did you set the proper pre-load on the bearing?
Did you inspect the U-joints and the guilbo while the driveshaft was on the ground?