vibration after tailshaft re-build

[VPRob]

So, I'm going up to Wollongong tomorrow to get the tailshaft balanced by an engineering firm that specialises in doing them. Quoted me $143 to do it.
I'm sick of mucking around with it and can't get rid of the vibration. Tried 2 positions at the diff flange and one is better than the other but I'm not going to start splitting the CV join and playing with the phasing cos that could take forever and the only thing I might achieve is to shake my fillings loose.
I'll post again once the balanced shaft is in the car

 

[Jonah 101]

Dont worry, they with fix the phasing when the shaft gets balanced.

 

[VK SL 3800]

Because of the CV joint the phasing isnt as critical as a standard 1 piece shaft, the front uni will usually be dead straight and not really "moving" so to speak. Some of the shafts ive pulled out are impossible to phase correctly.

The CV joint and the rear uni do the moving but mainly the CV, the geometry of the rear upper control arms keeps the back uni at a pretty nice angle where it doesnt do a lot of movement/ have a lot of working angle, so basically your front uni is at almost 0 degree and you rear is not from far that also giving a you a minimal working angle of the the uni joints. The idea of phasing is to have the unis canceling each others speed increases and decreases. one is doing the opposite to the other at the same rate in the driveline angles are setup correctly.

But with the 2 piece CV design in a commodore the front uni isnt speeding up or down (much if at all), so the rear will having nothing to cancel out and can create a vibration because of its own working angle.

 

[VPRob]

Tailshaft has been balanced and given a new black coat of paint at Daniel Engineering in Wollongong. Has been for 1 test drive and felt just fine.
Actually they also had to straighten the rear shaft just behind the CV join. They checked the phasing and said that was fine but I was told the balance was way out, almost off the scale, when they started on it. The phasing isn't meant to be exact as depicted in VKSL3800's earlier post diagrams but apparently that varies from model to model. Cost was $143 as quoted and I got some explanation of shims and alignment as well.
The bracket below the centre bearing affects sideways alignment as the holes are asymmetrical from side to side. It is marked for IRS and live rear axle and you point the relevant arrow towards the transmission. Shims are used to modify up and down alignment and the most important thing is to have straight alignment through the back of the tranny and the front section of the driveshaft, ie the front uni should be staying pretty straight. It can just be judged by eye. This helps ensure you don't get vibration under acceleration. I take the point above from VK SL3800 about the rear uni causing vibration and ideally that uni should be pretty straight as well. Thanks for all the replies. I now know more about tailshafts than I thought I ever would!

 

[redvpsenator]

Thanks, The price in the Gong is half what I was quoted here for the VS ute.

 

[VPRob]

Well I spent as much again on parts and I don't want to think about how many hours fitting them. Beats me how the shaft could be bent because it was smooth enough before I started on it. I just knew the unis were stuffed and thought I'd better do them. The CV had some wear but probably had plenty of life left in it and the centre bearing was noisy. I can see how I might have bent a yoke a little bashing away at the unis but I don't see how I could have bent the shaft. Anyway, all better now.
If your price was just for balancing then it sounds worth shopping around and maybe sending the shaft away

 

[Jonah 101]

I think it might have been your wooden clamps that bent them.

Usually just using an open vice is good enough to bash the unis out. Just rest the yoke between the two jaws and your'e away laughing.

 

[jas98]

A mob here in Townsville quoted me $200.00 plus $40.00 if they need replace the center bearing provided I supplied the center bearing.
Well what's new probably double Brisbane /Sydney price?

####!!!! i rang a driveline place today to ask how much to replace a center bearing in my ba xr6t if i supplied teh bearing and they said 33 bucks...i asked 3 times as i couldnt belive the price. neither no ford wanted 2k as you have to buy the whole shaft!