Alfa Romeo Owners Club of Australia Forum

Technical => 160 Series (90, 75, 164 Sedans) => Topic started by: GTVeloce on September 19, 2014, 11:41:43 PM

Title: Driveline vibrations/centre support
Post by: GTVeloce on September 19, 2014, 11:41:43 PM
My tailshaft centre bearing died so I had to pull it out and rebuild it. All was pretty straight forward except for the clutch but that has been covered in another thread.

My problem relates to the centre bearing support where it connects to the body. When I was tightening it I couldn't get close to the torque figure as the bolt(s) coming from the body were deflecting and I was just deforming the new centre support. So I left it there. Now, I have vibrations coming through the car and I presume they are related.

Did I miss something when I was putting it back in? I only replaced the centre up post and bearing with new. The guibos were still quite new so I didn't touch them. I made sure I replaced the spacers under the rear engine mount although I haven't checked the space between the tailshaft and the body is still 7mm.

Any tricks to torqueing the centre bearing to body?
Title: Re: Driveline vibrations/centre support
Post by: GTVeloce on September 23, 2014, 12:12:46 AM
Has anybody had a problem with torquing the centre bearing before? I've put plenty of tailshafts in before but never had a problem with this so not sure what is going. Unless the new centre bearing support is very soft metal compared to the original ones?

Thanks
Title: Re: Driveline vibrations/centre support
Post by: Beatle on September 24, 2014, 08:28:43 PM
Long time since I were under that part of an Alfetta, but from memory there are tube spacers between the bodywork/tunnel and the centre bearing support.  Do you have spacers in there?
Title: Re: Driveline vibrations/centre support
Post by: GTVeloce on September 25, 2014, 11:12:33 AM
No spacers and I don't believe there were any when I dismantled. Maybe you are thinking of the tube spacers between the rear engine mount and the body?

When you look at what the centre bearing support mounts to I'm very surprised because it looks so flimsy. It just appears to be the end of some box channel with a threaded rod protruding through. I will see if I can get a pic from somewhere and post.
Title: Re: Driveline vibrations/centre support
Post by: GTVeloce on September 25, 2014, 11:49:30 AM
Ok, I found a pic that what I am referring to. Please ignore the other text in the photo. The only suitable picture I could find was one from Shinycar's current build (I hope you don't mind me using the pic).

The centre bearing support just bolts directly up to this and is supposed to be torqued to 39-44 Nm.
Title: Re: Driveline vibrations/centre support
Post by: Divano Veloce on October 26, 2014, 12:02:19 PM
I had some trouble with the thread of the stud and nut being stripped. Couldnt come close to torquing one of the nuts....
Title: Re: Driveline vibrations/centre support
Post by: GTVeloce on October 26, 2014, 03:11:22 PM
Yes, I still haven't solved the issue. I never recall having any issues with Alfetta but I couldn't get close to the torque figure as was just distorting the metal underneath.

Still no further at resolving it but in the mean time I am just driving the car with a slight vibration. It's not bad but the car has always been silky smooth and I want to return it to that.
Title: Re: Driveline vibrations/centre support
Post by: Divano Veloce on October 27, 2014, 01:56:41 PM
Vibration was bad when i first got it back together after replacing the prop shaft. I had pinned the old tranny mounts as per greg gordons website. Once i removed the pins it was really good.

To get the nut torqued i added a new double thickness nut (twice the thread engagement) and a couple of washers to move the nut away from the stripped section of thread. This worked well. Sounds like a different problem to what you've got.