Signs Of Impending Drive Shaft Failure

SydneyRoverP6B

SydneyRoverP6B

Well-Known Member
Staff member
With the spate of differential drive shaft failures of late, I thought it apt to pose the question; Are there any warning signs beforehand or does all seem fine and then it breaks?

I would not expect one to break if the car in question has been driven with care, but if breaking traction whilst negotiating corners is common place, then sooner rather than later is more likely.

So far touch wood, I have never broken one. Has anyone reading this also never broken one? It would be interesting to see statistically how many forum members have had one fail.

Ron.
 
No warnings. I've never broken one, but I've fixed loads, particularly after engine tunes which included fitting new throttle linkage bushes.
 
A friend of mine had one fail while backing and tacking in a tight carpark one night.
I had one fail in my driveway one morning. I had been driving the car without issue. Got in the next day, started her up, slipped it into reverse and... nothing.
I don't think there are any warnings, you won't notice them being a bit twisted and one day they'll just give up. In both those cases more due to the shock of a direction change rather than attempting some un-Rover-like driving. If you were the paranoid type I guess you could pull the stubs out and look for signs of twist.
 
harveyp6 said:
No warnings. I've never broken one, but I've fixed loads, particularly after engine tunes which included fitting new throttle linkage bushes.
Click to expand...

Two funny stories: The first P6 (Rover period, in fact) I was involved with was a 67 TC that I talked my just-out-of-high-school friend into buying in 1973 because I was still in school and had no money at all. A couple of years later, while in college, we were taking a final drive in the car before the insurance expired (pauper students and all). At 11:59 that night, Kim pulled into the parking lot opposite the apartment we lived in and started to do a couple of donuts. On the second time around, the engine ran free and the car stopped sliding. He had broken both shafts at the same time! I suspect that they would of failed fairly soon anyway, but it was entertaining at the time.

I also broke a shaft, perhaps in the same car or a '66 TC I had around then, about 6 years later. This time I was having a heated argument with my girlfriend about something. I got so angry that when I went to leave after kicking her out of the car on the side of the road, I dumped the clutch under full throttle. The shaft broke and the car didn't move. Which actually was a good thing in the end, the humour in the situation defused the argument and life went on more easily.

Yours
Vern
 
One went on me just last week whilst reversing a car towards the ramp.
The thought of inspection was enough to just give up!
I knew what it was as soon as it happened, the noise is a little shocking however :)
Jim
 
Hi, in my early days of P6b ownership I had about 3 or 4 go. One car had a BW35 that was
past its service life but still working if nursed, but if I booted it it would let go, the engine
would rev up then the drive would come back in with a bang and we would be off. :oops:
The others I put down to changeing from D to R or vice versa while going the other way
usually with some throttle on, Folly of youth. I just used to go up the breakers yard and get
a pair usually out of a 4 pot SC because I reasoned they would of had an easier life. In fact
I nearly always carried a pair around in the boot, and I still have a couple of pairs in the
workshop, just in case. :wink:

Colin.
 
harveyp6 wrote,...
No warnings.
Click to expand...

I thought that may have been the case, but kind of hoped otherwise. It really is a pity that Rover didn't over engineer the differential specifications. If they had of, the assembly would have been pretty well indestructible, like a Ford 9" diff.

Ron.
 
Hi Harvey, I have never had one of these fail but some years ago when we were on holiday in Bournemouth I had this terrible squealing noise from the back end usually when accelerating, to cut a long story short this turned out to be the needle bearings in one of the universal joints that had more or less dissintegrated, I did change all 4 joints at the same time and I did note that there was a sort of powder (orange/red colour) this was the joints becoming dry and the needle bearings giving up. As for the prop shaft, never had a problem with that. (The car has covered 170,000 miles and is 43 years old)
Best Regards
Dave
 
DAV8 wrote,...
As for the prop shaft, never had a problem with that. (The car has covered 170,000 miles and is 43 years old)
Click to expand...

Hello Dave,

Do you know for certain that the universal joints within the tailshaft are the factory fitted originals? Would you happen to have some photographs of them that you could post please?

Ron.
 
I've never had one break but I'm beginning to think that Bruiser's juddery take-up is a UJ in the passenger-side driveshaft. Not the first time but I really must stop putting it off & attend to it & other matters that need attention.

Harvey, with admirable foresight & not a little thought for his wallet, sold me a pair of driveshafts with good joints some time back so it should be a simple swap job. And if they fail? Guess who's going to "help" me to fit new joints. :wink: :LOL:
 
I do worry about this as I have to pull onto a busy A-road every evening from a standing start, its a bit "do or die" so you have to properly go for it sometimes, with the result that occasionally, particulary when damp I do light up the rear end. Whenever this happens I instantly back off the throttle and wait for it to grip before applying the power again.

Better start looking for some spares I guess! :?
 
Hi, I used to think they were prone to breaking because they were so short i.e. there was
no decent length of shaft to wind up to absorb the shocks. I know that drag racers using
beam axles used to put pinstripe along the length of the shaft and once they had wound up
¼ turn they changed them. But P6 shafts don't break on the shaft itself they break within
the splined part which is the weakest part because of the sharp edges from the machining.
Perhaps Sowen or the rally lads can tell us if the Jaguar shafts are larger diameter or a
different grade of steel.

Colin
 
Just to avoid any confusion, the drive shafts are short splined arrangements that reside on each side of the differential. The discs mount to the flange of each drive shaft, and the half shafts, which contain two universal joints, then bolt through the discs and into each drive shaft flange.

catboy wrote,...
Is it not possible to get these remanufactured possibly stronger?
Click to expand...

To make them stronger, they would ideally need to be larger in diameter. A small increase in diameter will deliver a very much increased resistance to twisting.

Ron.
 
symes wrote,...
Mine so far has'nt broke a shaft--however it has destroyed a few couplings(spiders)
Click to expand...

I assume by couplings, you're referring to universal joints?

Were they of the greasable variety Symes?

Ron.
 
symes said:
Mine so far has'nt broke a shaft--however it has destroyed a few couplings(spiders) :( :(
Click to expand...

The easiest way to make them stronger, somewhat counterintuitively, would be to shorten the splined area so the splines are completely contained within the differential side gear. The failures begin with the shaft twisting the splines slightly, which very highly loads the upper edge of the splines where they exit the side gear. Eventually, cracks appears and some time later the cracks propagate and the shaft twists off. If the entire spline is inside the gear, the load is applied uniformly along the length and depth of the spline and I'd bet failures would be rare.

Yours
Vern
 
Vern Klukas said:
symes said:
Mine so far has'nt broke a shaft--however it has destroyed a few couplings(spiders) :( :(
Click to expand...

The easiest way to make them stronger, somewhat counterintuitively, would be to shorten the splined area so the splines are completely contained within the differential side gear. The failures begin with the shaft twisting the splines slightly, which very highly loads the upper edge of the splines where they exit the side gear. Eventually, cracks appears and some time later the cracks propagate and the shaft twists off. If the entire spline is inside the gear, the load is applied uniformly along the length and depth of the spline and I'd bet failures would be rare.

Yours
Vern
Click to expand...

Yes that sounds like a sensible modification, you would need to end the splines with in the hub and radius the spline to shaft interface area in a gradual manner.
 
You must log in or register to reply here.
Back
Top