W108 Intermediate Driveshaft Support Question...

[Arthur Dalton]

I am from Milford , NH., but have a home in Fl.

I will be up there next week for a month.

[nhdoc]

nevermind that last one, I found it out in Amherst...thanks.

[nhdoc]

Originally Posted by Arthur Dalton

I am from Milford , NH., but have a home in Fl.

I will be up there next week for a month.

Well, if you need the use of a shop with a lift while you are here drop me an email. It's the least I can do after all the tips you've shared.

[Arthur Dalton]

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well, thanks for that offer, but I have access to Towne Lynes Shop....
[ I used to do Benz Consult work there].

I will email you when I arrive.

[nhdoc]

Originally Posted by Arthur Dalton

<>

well, thanks for that offer, but I have access to Towne Lynes Shop....
[ I used to do Benz Consult work there].

I will email you when I arrive.

Thanks...I'd love to have you take a look at this if I don't get it straightened out by then. I should have some parts next week and will tackle what I can. I may try and make up a spanner to check that nut when I do the flex joint...it should be something I can make up to at least check it.

[Arthur Dalton]

Guys make them out of an old 7/8 socket.
If it is loose, you will know right away b/c you will be able to turn it with needle-nose pliers [ using the noses to slip into the slots.]
You will also notice a complaint of a jumpy speedo, specially when letting off the gas...
Another important oversight when working on this drivetrain is guys tighten everything up with the chassis hanging on a lift.. The car has to have a loaded suspension and should be rolled back/forth a few times to settle the rear trans mount position and to set the driveshsft spline coupling before tightening .. this is of the ULTIMATE importance.. failure to do so will eat the disc and upset the drivetrain, just as a bad rear trans mount will b/c it changes the drive shaft geometric angle.

[nhdoc]

I guess I need to find a drive-on lift to do this project

...thanks again for the tips!

[Benzcrusher]

I may have missed it but change out that caged ball bearing as well as the doughnut. The bearing is most likely shot after 30+ years of service.
To replace:
seperate both drive shaft sections AFTER match marking them
remove the large C clip
pull the bearing off with a puller.

The bearing is cheap and was used on most MB's from ~66-~90

[Tony H]

If you suspect your driveshaft is out of balance you can send it to Driveline service of Portland http://www.driveshafts.com/bmw/
They specialize in European driveshafts. I used them to rebuild the driveshaft in my 3.5 coupe. They will send a prepaid shipping tube for your driveshaft, totally rebuild it and send it back. You will esentially have a new driveshaft when they get done.
Anytime you dissasemble your driveshaft it must be spin balanced so if you take it apart to replace the bearings it could end up out of balance.
Tony

[JMela]

Tony, about how much was your driveshaft rebuild?

[Arthur Dalton]

If shaft balance is suspect , you can do a couple of hose clamps in differing positions , trial and error ............

[nhdoc]

I received the new flex disc and donut today and will replace them and use the "weight on the suspension" method of aligning everything before condeming my driveshaft. I strongly suspect my shuddering vibration is caused by one or both of the parts being bad...will report back later this week.

[Tony H]

It was not cheap but my coupe has a 3 piece drive shaft with 3 u-joints and 2 centerbearings. They install servicable u-joints in place of the staked in place sealed units. It ran a bit over $500 but the piece of mind knowing it's done right was worth it to me. A 2 piece shaft would be considerably less I'm sure.
Tony

[nhdoc]

I finally got to this today, just before the car goes to its new owner this weekend.

It turns out the center bearing was bad and you could feel it trying to spin it that there was roughness and resistance and there was also a slight bit of uneven resistance in the rear u-joint in one axis.

Since that joint is essentially unservicable and not easily replaced I elected to just replace the center bearing, rubber boot and bushing and hope for the best.

Turns out this eliminated about 90% of the shudder/vibration I was seeing under load.

I am certain the last 10% is probably from the u-joint but frankly considering how bad it was and how much better it is now I can't see spending a lot more $$$ to get it perfect, and its new owner will be happy with it like this I am sure.

It could also be that the new bushing that isn't all compressed has the center bearing sitting higher and the u-joint doesn't hit as much of the rough spot any more too...either way, the center bearing was most of the trouble...a cheap, easy fix.

[MunichTaxi]

either way, the center bearing was most of the trouble...a cheap, easy fix.

Exactly the problem I had with my W108. Once replaced, no more vibration at freeway speeds.