NEED HELP FAST! Is this right!?

[Stu]

Is this the right orientation for the driveshaft/center support bearing on a 325i?

We don't want to put the heatshields/exhaust on until we have the driveshaft perfect.

Thanks

[RCWells]

As opposed to what?

[RCWells]

I mean, it looks like the support is lined up just fine, and the driveshaft in place. Did you separate the driveshaft or remove/reinstall together? IF you separated, make sure you line it up with the marks otherwise, it should be fine.

Not sure exactly what you are asking.

[RCWells]

As a matter of fact, that white dot painted on there is one of your markings for lining it back up.

[Stu]

RC, Yes, we lined up the splines correctly.
The 'cup' shaped nut that is tightened on....what is its purpose? Is the gap where the splines are normal? It's been 3 years since I've had a driveshaft apart and cannot remember everything.

[Brew]

Make sure there is minimal preload on the center support bearing. I always wait to tighten it down until I have the driveshaft mounted to the tranny and the tranny crossbrace mounted.

[Brew]

Thats a normal gap with our s50/260 setup.

[Stu]

Brew, this is a stock 325i M20 driveline (spece30 car).

Do we need to tighten the fuck out of that cup nut?

[RCWells]

I believe that looks about right for the gap on the splines. I just had mine off recently replacing the guibo, and IIRC I had about that much left over too. I think the cup shaped nut has to do with the "preload" Brew mentioned. Don't tighten it up too much until everything is in place, then snug it up.

[VAPORBLADE]

OT:

But that would be funny on a tourque wrench - 100lbs...200lbs...300lbs..."tighten the fuck out of it"

[AndrewBird]

Preloading is pushing the center support bearing so the rubber around it has pressure on it. That is why the bolt holes to mount the CSB are slotted. I believe it should be pushed forward (towards the front of the car) but I could be wrong. Someone correct me if I am.

The big cup shaped nut thing should be loosened while sliding the driveshaft together and then tightened down slight afterwards. All it does is help hold the splined shaft in the splined hole. Really, if you didn't mess with it, you should be fine.

[Jand3rson]

Preloading is pushing the center support bearing so the rubber around it has pressure on it. That is why the bolt holes to mount the CSB are slotted. I believe it should be pushed forward (towards the front of the car) but I could be wrong. Someone correct me if I am.

You're correct, but I've been told by Trent and a few others that this isn't actually necessary at all. The Bentley and everywhere else says to do it, but Trent says he's never done it, and I didn't do it on my current CSB, and that was almost a year ago, and I've had no issues.

[george graves]

Yea - but forceing the Center support berring an 1/4 inch forward when you bolt it up - it what two 13mm bolts? - and you don't need a pry bar - just your arm - it's to seal the inputshaft, and to let the DS "float"

Bigest issue is if you seperte the DS that you'll have balance issues. (the thing rotates at huge RPM under the car!!!!!!!!!!)

Hope that helps...

[Brew]

You're correct, but I've been told by Trent and a few others that this isn't actually necessary at all. The Bentley and everywhere else says to do it, but Trent says he's never done it, and I didn't do it on my current CSB, and that was almost a year ago, and I've had no issues.

Exactly. I believe the spec is 5mm forward, but I was taught to not preload them and after maybe 50 or so cars in the last 1.5 years I've never had an issue.