Tailshaft - balance, vibration?

[losh1971]

Because to have a specific die made with 4 stake raised sections in tool steel and hardened, is quite expensive.
It would only make sense to spend coin on these things if you have enough work flow.

Fair enough.

But what I originally said still stands that the OP will hope it's not the uni that is the problem as it is a very expensive job to have a new uni fitted, and very few places do them. It's probably not a lot more to buy a whole new shaft.

 

[Immortality]

The problem with staking is you need to ensure the uni and bearing cups are centred properly in the yoke or shaft where as with the older design with clips that is all done for you.

 

[losh1971]

It would also be likely that someone has been bashing away with a BFH if the uni on a VE has failed. They don't have the flexing motion older ones did and so don't wear out anywhere near as quick.

 

[Immortality]

Flexing motion?

 

[losh1971]

Flexing motion?

I can't think of another word to describe it. Earlier unis pivot on the bearings a lot more than the VE ones do. But you already knew that and likely know the correct term?

 

[losh1971]

I was told by the place who rebuilt my TS they don't often see VE's in for uni replacement from normal wear and tear due to the less "flexing" for want of a better word.

Having said that they see plenty of VE unis needing doing (one or two a week) from across the state when people jump on YouTube and have a go themselves at replacing the bearing.

 

[Immortality]

Probably working angle for a uni joint. Uni joints actually need a minimum of 1° working angle or they fail very quickly because the rollers in the bearing cup don't move and they eat the bearing surfaces.

It's really poor form from Holden to change from a CV joint to a uni joint. CV joints are perfect in the middle of a drive shaft because it's a constant velocity joint, that means no matter the angle, the shaft speed going into the joint is always the same as the shaft speed coming out of the joint where as a uni joint that is not true, it will accelerate and decelerate as it goes through it's angular motion. This is why uni joints are normally in pairs and phased so they cancel out the speed variation.

 

[losh1971]

Uni in my VE had done over 210k when I had the shaft rebuilt and we kept the original uni as it was still in very good cond. The bearing was replaced and the shaft balanced better than it was from factory, IIRC it was rebalanced to be within 2gms whereas factory is apparently within 5gms. I'm not fully understanding why a centre uni is not a good option if they don't wear out like the Gen II ones do? The couplings on the other hand, well I don't love those as they are what I'd consider to be the weak point on a Gen IV.

 

[shane_3800]

Probably working angle for a uni joint. Uni joints actually need a minimum of 1° working angle or they fail very quickly because the rollers in the bearing cup don't move and they eat the bearing surfaces.

It's really poor form from Holden to change from a CV joint to a uni joint. CV joints are perfect in the middle of a drive shaft because it's a constant velocity joint, that means no matter the angle, the shaft speed going into the joint is always the same as the shaft speed coming out of the joint where as a uni joint that is not true, it will accelerate and decelerate as it goes through it's angular motion. This is why uni joints are normally in pairs and phased so they cancel out the speed variation.

well at 1 degree the speed change will be so small that the rubber couplings will easily eat up the heat.

On a diff where the angle gets pretty heavy then yea that would apply.

 

[Immortality]

It probably has to with working environment. On a IRS cars the whole drive shaft is tucked up and out of the way and isolated from the suspension where as on the earlier Commodores the diff end of the shaft is part of the unsprung mass of the rear suspension so the uni would see more abuse and much more open to the road environment under the car. I also think grease quality might be part of it. You'll note it was only ever the drive shaft end uni that seemed to show wear and tear, the gear box end always seemed fine. Most of the angular difference from the rear suspension would have been taken up by the CV joint.

well at 1 degree the speed change will be so small that the rubber couplings will easily eat up the heat.

On a diff where the angle gets pretty heavy then yea that would apply.

Yeah, no doubt that is what Holden were banking on.

Personally, I prefer the older style driveshaft that I can fully service or rebuild in my garage.