Unbalanced Drive shaft

[850Mad]

I removed the drive shaft because I had a vibration. (Which of course means removing the exhaust system to get to the drive shaft.)
I noticed that one of the joints was rusted and was NG, which I assumed was where my vibration was coming from.

I saw on the forum that someone replaced the U-joints on the drive shaft for a vibration problem. So I replaced the U-joints. I got all the right dimensions and after I reinstalled the drive shaft with the new U-joints there was still a vibration.

I used to have a leaky differential seal, which I replaced by removing the differential. (Not sure but I think that the drive shaft vibration probably caused this seal to fail.)

So I decided now, with the differential removed and repaired, to remove the drive shaft again. (And of course that meant removing the exhaust system again.)

I took the drive shaft to a reputable balancing company and the guy said it failed -- it has a vibration that he cannot do anything about. Basically it comes down to that the yolks are not centered in the shaft. He said this is a typical problem with this type of drive shaft, when somebody tries to make the repair without having the original parts (which you can't buy). You would have to buy the whole drive shaft.

OK, so now I am making an attempt to buy a new drive shaft.
Nobody makes them for my model, that I can find.
I looked online and the diagram doesn't show the correct flange needed to be installed to the transmission. In the ones that they show, the drive shaft uses a rubber coupling. My 1993 BMW 850 does not use a rubber coupling.

I'm sure you guys know about this.
Does anyone have any advice?

My only option right now is to engineer the U-joint couplings so they can fit a standard U-joint, so it can be replaced.

Maybe I am being picky. But this is a BMW 850 and I want it to run as smooth as it was when new.
I'm open to suggestions. (Please help )

[petejk]

Here’s a link for a driveshaft for a 850 automatic. About $850 after core return:


https://www.turnermotorsport.com/p-5...-transmission/


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[rjjablo]

The Canonical Thread. Wrote it myself for posterity

https://www.bimmerforums.com/forum/s...nt-Replacement

[cartoonz]

buy a new one... with serviceable U-joints
www.driveshaftpro.com

[TTTXGreg]

buy a new one... with serviceable U-joints
www.driveshaftpro.com

Ditto. I have replaced driveshafts on 3 of my 8's in the past. First attempted to bring old to driveline shop and they wouldn't touch it. A new one is your best choice.

[cartoonz]

...and they are less than $500

[petejk]

As I’ve already purchased a CSB and CV joint, and I can’t feel any play in the u-joints, I tried to work on my drive shaft this afternoon.

I had a feeling the 19mm nut holding the two halves together was going to be a pain and I was right. I almost gave up, but loosened it up in the end.

Now I’m trying to separate (after marking) the halves. Is there a trick to doing this?




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[rjjablo]

If should just come apart

Or

Clamp driveshaft in a vise by the welded end, not in the middle of the shaft

Hammer and a Block of wood and you should be able to tap it off it is only held on by the bolt

I took the center bearing off my POS Dodge Pickup with an Angle Grinder, rusted on. Tap it back on with a length of PVC Pipe

[petejk]

Clamp driveshaft in a vise by the welded end, not in the middle of the shaft

Hammer and a Block of wood and you should be able to tap it off it is only held on by the bolt

I should have thought of using the vice. Thanks -
I’ll give that a shot in the AM


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[cartoonz]

I should have thought of using the vice. Thanks -
I’ll give that a shot in the AM

When you finally end up needing a new driveshaft - driveshaftpro is the spot

[petejk]

When you finally end up needing a new driveshaft - driveshaftpro is the spot

On closer inspection with driveshaft in a vice, there is play in the u joint. I guess I will be buying another


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[Fatandre]

When you say buy a new one you mean from the dealer?

[rjjablo]

This is how I did my U Joint

https://www.bimmerforums.com/forum/s...nt-Replacement

[petejk]

This is how I did my U Joint

https://www.bimmerforums.com/forum/s...nt-Replacement

I’ve read through your thread a couple of times, but I’m not confident enough that I can do the u-joint replacement myself.

When you say buy a new one you mean from the dealer?

I’ll contact the business that Cartoonz recommended, and see if they will deliver to as far afield as GA. The price seems good


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[cartoonz]

When you say buy a new one you mean from the dealer?

absolutely not. DriveshaftPro is a network of driveline shops across the country. They build brand new units with servicible u joints - and they are less than $500

[Fatandre]

OMG. I need one of those for my manual e31

[petejk]

OMG. I need one of those for my manual e31

DriveshaftPro didn’t have any cores left for the v12 manual driveshafts. A new driveshaft would have cost ~$800, and I didn’t want the hassle of mailing my driveshaft.
I ended up going with a new driveshaft from Texas Driveshaft Specialist for a couple of hundred dollars less.


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[JDP530]

Dorman manufactures a replacement driveshaft but only for the manual for appx $600.00.

https://www.dormanproducts.com/gsear...rive%2520Shaft

[petejk]

Dorman manufactures a replacement driveshaft but only for the manual for appx $600.00.

https://www.dormanproducts.com/gsear...rive%2520Shaft

That’s about what I paid, also with serviceable U joints.




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[JDP530]

I dont know why they wouldn't build a driveshaft for an auto considering there are many more autos on the road than manuals.

[petejk]

So I’ve been experiencing the worst possible luck with getting a replacement driveshaft.
I contacted Driveshaft Specialists Inc, and they built me one, and sent it out in September. I didn’t think to check fitment at the time...

A couple of weeks ago I tried to bolt it up, and the flange was smaller than the guibo (I.e less than 110mm across).

I sent that driveshaft back, and received a replacement which had the same issue. Perhaps I should have cut my losses, but I accepted a second replacement (third driveshaft), which was again incorrect.

Apparently the specifications in the online catalog the company was using to build the driveshaft are incorrect.

So I ordered a Dorman from Summit, which arrived today. And you’ve guessed it - the flange is again incorrect. It looks like Dorman spec their driveshafts from the same information set.

In order to get on the road again before the new year I need to separate the front and rear halves of my existing driveshaft, and fit a new guide bush, center support bearing, and CV joint, which I have - unfortunately I don’t seem to be able to knock them apart. The bolt is loosened, but they don’t seem to want to budge. Does anyone have any ideas?

Picture of Dorman, and the guibo that won’t fit:



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[petejk]

On second thoughts, I’m not going to mess with it again. I’ll take it to a local shop to install the CSB on Monday


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[Jetmex]

I have had great luck with https://www.drivelineserviceofatlanta.com/ on the three or four Z3 shafts I sent in for rebuild. I'd at least reach out to them especially if you have your original still.

[Liquidity]

Fleetpride makes/rebuilds driveshafts. Just so you know.

[petejk]

Fleetpride makes/rebuilds driveshafts. Just so you know.

And they’re close - that’s another place for me to hit up on Monday. Thanks


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